Felly, fel ffasag ar y cynllun am 30 mwy o'r dynod y cymuned ddiwuniaeth yw 18. Rwy'n byw i'n rwyf yn ddiwu'r llei, reifwyr i'w cymdeithasol, i'w ddiwg gaelol i amlwgfod. Ryn ni'n i'n ddiwg ei ffordd o eich perthyniadau, roedden nhw i gael mwy o'r dynod o'r cymuned ddiwuniaeth, ond yn felw ydych yn cael ei ddwynau i weithio? Rwy'n rhaid i fynd i dd благодарu eich Rhagorau Llywogol Cymru ar gyfer y Llywodraeth Llywodraeth, Mae'r gweithio y ddisgwlad ddim yn gallu'r bywyr, ac mae'n cydweithio i'r ddod o'r seisio'r bywyr o'r ddataf a ddataf mewn prifysgawr yn ei gynhyrch, a'r oedd yn cydweithio'r ddataf i'r anolod. Hefyd, yn ddod, yw'r ddataf i'r anolod. Mae'n ddod o'r ddataf i'r anolod i'r anolod i chi'n gydag. Mae'n ddod i'r ddod i'r ddod i'r ddod i'r adnod Lucy Hunter Blackburn, yng Nghymru, Blackburn MacKenzie, Professor Jackie Castle, Head of the Department of Primary Care and Public Health, and the Director of Research and Knowledge Exchange at the Brighton and Sussex Medical School. We have Jerry McCartney, Head of the Public Health Observatory Division at NHS Scotland, and Professor Susan McVey, Professor of Quantative Criminology at the University of Edinburgh. Thank you all again for coming. We were also due to take evidence from Ipsos Moray this morning, however, due to a lack of video conferencing facilities in their office, we have been unable to do so. Just before I ask an opening question, as I said, the main purpose of the bill is to ask questions on gender identity and sexual orientation on a voluntary basis. In the course of scrutinising this very short bill, the committee has received evidence expressing concern about the conflation of the categories of sex and what is called gender identity in the bill. A number of our submissions have suggested that this could be problematic for the gathering of data, as well as setting a precedent. The census team in their sex and gender topic paper says that sex is a key demographic, and sex data is vital for assessing various demographic statistics used by local government to inform resource allocation and target investment. I note that the women's budget group in another submission has said that they rely on sex-disaggregated data in order to analyse the economic and social impacts on women of public policy. I will turn to Lucy Hunter-Blackburn first, because you have submitted written evidence expressing those kinds of concerns. I wonder if you would like to outline them, particularly in the context of data gathering. The starting point is the purpose of the census, and you are looking at the census existing to gather data, which is as useful and as reliable as possible. By reliable, we mean that you are getting the same kind of answer from the same kind of person. You know what your answers mean, so that it can be used by people who are planning and providing public services. Above all, what the census does exists for a very specific purpose of data gathering. I think that the main point that I want to make before I say anything else is that there is clearly no disagreement at all about the value of gathering more data on the population who identify as trans, and it is immensely valuable. The census is a very good place to do that. The existence and insertion of the voluntary question does not seem to be a matter of particular contention here, and all the debate is about what happens with the question on sex. I think that if I can make three points there, convener. First of all, we think that it is very important that the census is continuing to capture data on sex as a protected characteristic on terms that are consistent with the Equality Act. The Equality Act clearly has a two-category definition of sex, male and female. It is not a no more category than two. Introducing a third sex category, as is proposed, is what the bill is being amended to enable. That would take you out of consistency and compliance with the Equality Act in the way that that is framed. That would definitely have issues for quality monitoring and the data is used there. The other point that I would make is that there is no evidence that service users have demanded moving away from a binary sex category in the census. There is no evidence at all. In fact, the NRS is quite clear that this is not driven by a census user wanting an extra third category. There is a different sort of point, which I think is also important here, which we think you need to avoid using the Census Act to set a precedent on the statute book which conflates sex with gender identity because conceptively they are quite distinct things. The Census Act does not feel to us the right place to be introducing new ideas about how to conceptualise sex in law. That is a debate that could be had, but not in this context. Our view is that the definition of sex in the Census Act 1920 should remain as it is now. It is aligned with the one in the Equality Act and, indeed, with other legislative contexts where sex is used. In marriage birth, death certificates, we use a two category version of sex, right across the legal context. That would suggest that what you do not want to do is amend paragraph one of the schedule where it talks about sex to introduce the additional words. That would mean that, however, you would also need to introduce gender identity in the same way that it introduces sexual orientation as a voluntary topic. That would be my key points. Just for the record, there will be a gender identity or trans question. That is clear, and we will consider the wording of that at a later date, but that is in addition to the sex question. Do any other members of the panel wish to comment on this point? I might comment in relation to the use of such data. I mean, obviously, there are many, many uses of data on sex, some of them more important than others. I think it's important to look at the wider context of data on sex. It's really important that the census is a point of reference, but with the growing use of administrative data sets and a couple of censuses away, the census will look very different, will draw on NHS data, will draw on all sorts of data. It's really important that there is consistency of the data on sex with other data sets for the credibility of the census as such an important data resource giving information at low level on quite small populations. The various collectors of routine sex data will have public equality duties. It's very important that people don't stop looking elsewhere because the census data is seen to be problematic. I think there is a real issue about precedent and credibility for the census. I would say for the purposes that the many data sets are used to draw on sex data, it is absolutely key that we do have a good representation of the definition in law as it currently stands. That, of course, can be discussed and moved on, but as it stands now, it is important that it is consistent with other data sets. For health purposes, what is the importance of that? There are many areas of health where biological risk is very important. Those interact with and in some areas very importantly interact with gender identity, but biological risk for many conditions and treatments and outcomes. We know that sex is a big differentiator of outcomes for many conditions. It's important that that is robust in order that we meet our duties and they are many and they are often not well met in the fair provision of effective treatment to men and women, which may not always look the same. It's important for the committee to differentiate between two slightly different things. The provision of services for individuals and population level data. Clearly, we don't use census data to institute services for individuals, we don't use it to identify services for individuals. Notwithstanding the points that have been made, we wouldn't use the census to identify people for screening or other purposes like that. We would use the existing health record data sets, the CHI, the community health index data sets and the clinical records associated with those to identify individuals, for example, who are in need of particular services. However, the census is clearly a key data source for resource allocation and planning at a population level. It's important to recognise the difference between those two data sets. In Scotland, we have some very rural areas where small differentiations in the census or any data would be significant in terms of resource allocation in a rural area with a small population. You use the census for a whole variety of purposes, including the denominator data that calculates the index model deprivation and other indices, right down to very small geographical areas such as data zones. All the data that we collect in the census is used through other purposes to make these more precise resource allocation decisions for local areas. Professor McVey, your area of criminology will have an impact on that area? I'm not really here to speak on the basis of criminology per se. I'm really here as the co-director of the Administrative Data Research Centre in Scotland. Scotland is really at the forefront of data linkage and census sits at the core of data linkage. We have what we call a census spine. The census forms the core of how we link all other administrative data sets together. It's vitally important that the census is accurate in terms of its measurement of the characteristics of the population in order for us to have a strong spine to which to attach other data sets. In research terms, it's a fundamental property of research that, if you're designing a questionnaire, you need to be very clear about what you're measuring. I might say possibly controversially that I think the general registers of Scotland got it wrong in 2011 when they redesigned the census at that point and they conflated sex and gender identity into one question. I think we're now trying to kind of disentangle that. Arguably, the measure that we have of sex in 2011 census is not accurate. One of the issues that you've probably realised from your various papers and discussions is that the issue of sex and gender is not a simple one. It's actually very complex and there are lots of different dimensions to it. In some respects, trying to boil it down to two questions in a census is somewhat problematic and I think that's probably why we're all round the table today trying to kind of disentangle the different aspects of it. From a research point of view, we know that there are certain conditions, medical conditions, for example, that are sex-related. Regardless of what your gender identity is, if you were born a man or born a woman, there are certain medical conditions that you will be more likely to face. We also know, and this is probably more my area, that there are certain social processes that are differentiated for men and women. There are sex-related biases, discriminations and forms of inequality that don't necessarily go away if you change your gender identity. It's very important to distinguish between sex on the one hand and gender identity on the other in order for us to be able to understand, for example, do trans women have worse outcomes than cis women and do trans women have worse outcomes than cis men? If we were to properly understand the relationship between sex and gender identity and how that impacts on other factors such as health, such as the likelihood of getting a job, such as attainment within education, we need to be able to disentangle those things and have a much clearer picture. You referred back to 2011 when you said that the NRS got it wrong when it conflated sex and gender identity. It's been put to us that there were notes that explained that, but we've actually asked for a copy of the census form and the guidance notes are not on the census form, they were somewhere online. Do you think that people understood that that had happened? Some people will have gone to the trouble of reading the notes and understood and other people won't. The problem is that you will have some people interpreting that question as their biological sex and you will have other people interpreting the question as their gender identity, so therefore you have a question that you don't really know what you're measuring for any particular individual. In addition to that more general conflation, there is a proposal to offer a third option in the sex question in 2021, so it would be male, female, other. Possibly the wording isn't decided, but that's the suggestion. It's not set in stone, but it's a suggestion that might happen. How would you feel about that? I've spoken to members of the LGBTQI community and the word other is highly offensive for a start. Many people from that community do not consider themselves to be another. Fundamentally we're still conflating two things if we use another category. Sex is about either biological or legal sex, whichever you decide to use, whereas gender identity has non-binary options, but sex doesn't have non-binary options. Even someone who's intersex, which is essentially a kind of medical condition, even someone who's intersex is generally an intersex male or an intersex female based on their physical and genetic composition. You would still be conflating two things if you add another category. The main thing is to consider what the different dimensions of gender identity are and to have a series of questions that allow people to adequately express how they feel about themselves and keep sex separate to that. We must be very clear about what we mean by sex, have guidance in the documentation that's very clear, and then have a publicity campaign around the census that explains why the questions are the way they are. It's not the purpose of the census to try and make people choose something that they don't want to choose to represent themselves. The purpose is to measure the characteristics of the population and then to use that data to properly understand how things like health conditions or social experiences, how education is delivered. In the era of measuring inequality, we know that many people from the LGBTQI community feel that they're discriminated against. We won't properly be able to understand how that manifests if we don't also understand what their sex is. I want to ask some questions about the voluntary aspect of the sexual orientation and gender identity, as it's phrased at the moment, questions. We had evidence from Equality Network and the Scottish Trans Alliance that said that it shouldn't be assumed that adding those questions to the census would give an accurate count of the trans and LGBTI community. It might be the questions that were seen as being too sensitive that some people would be reluctant to answer them. I suppose that it raises the questions if the questions are voluntary and the data is not going to be reliable. Is it worth asking those questions at all, or do you think that it is helpful data and information that would come from asking the questions on a voluntary basis? We do have some evidence from the sex and gender topic report of what the take-up was of the voluntary question. One thing that does come through there was that the take-up was quite high. I think that from memory it was something like 94 per cent of people when it was road tested had put something in. The initial evidence is that people will respond, but others may wish to say a bit more because what we got that didn't tell you was what the response rate was among people who were trans identified and clear that that's where it matters most. The evidence is over three now waves of the national sexual attitudes and lifestyle survey is that you can get very good response rates even out of the census for these kind of questions. Clearly, it is likely that questions about gender and sexual orientation and trans identity are likely to change over time because they are quite shifting things with social change, but there is a very strong evidence base that you can get reasonable quality data on many of those aspects that has been done in many settings with general population samples. That would support acceptability. They are complex questions. Some people will have a better understanding than others. I think that there is also evidence that there will always be reasonably high non-response rates, but I think that there is no doubt from many studies of many kinds and population samples that you can get useful data that can inform policy. Just to highlight the religion question in 2011 was voluntary, but we've made huge use of those data. We've been able to explore the prevalence of different religions across Scotland and also use that to think about discrimination and other important facets of society as a result of that. There have also been examples where we've been able to link data in a very complicated way to avoid individual identification to make better use of the ethnicity data within the census. That's allowed us to explore differences in life expectancy, differences in hospital admissions for people who report on different ethnicities. That's really moved on the evidence base around what we know. For example, the life expectancy of white Scots is much lower than many of the ethnic minorities in Scotland, but hospital admissions for certain conditions is higher for some of the ethnic minorities. Those are things that we wouldn't have known otherwise without those questions in the census. I know that the ethnicity question wasn't voluntary, but we can make similar use of those data even if they aren't completed entirely because you'll still get a feel for what the differences are between groups. The definitions that the bill uses—I'm not sure if you've had a chance to look at that actual bill. It's a very short bill, and there's already been some responses from the panel this morning on the use of gender identity, which, as Lucy Hunter-Blackburn says, is included in paragraph 1 of the bill. There has been a suggestion that gender identity, when it comes to the voluntary questions, can be changed to trans and be more specific about what the question is in relation to. I wonder if you'd supported that. I think that that would work better than what we had before us. It's really just changing gender identity to trans with changing the wording. Professor Susan McVeigh talked about the last census of 2011 and how robust the data around the sex question was, given the guidance that was online, and not all was that obvious to people. Has there been any unintended consequences from the decision that was taken in 2011, or is it too early at this stage to make comparisons, or can you see any problems or issues that are brought by not being cleared about that question? Is it possible to put a question in the sex category that we can all be clear about how people are going to answer? I'm trying to remember all those questions. Can we make a question clear about sex? Yes, we can.  That would be very clear. I'm trying to follow back the train of thought. For you, it's particularly hard to tell because you can't disentangle the data if you've conflated two different things together. We would only potentially know that by getting the questions right in the 2021 census. We can link censuses together, so we would be able to link back to the prior census and identify the proportion of those people who interpreted it as their biological or legal sex and the proportion of people who identified as a trans man or woman and put their gender-preferred identity in the census. The honest answer is that we don't know the numbers. That's why the census is so important. The census is the only source of data that we have that's an entire population measure. Being able to measure the population accurately is really important, but more important is asking the questions that are clearly differentiated so that people understand what they're asking. I mean, you also asked about the questions that were proposed, I think. Is the use of gender identity, whether that's a definition, to put on the face of a bill that is clear what the questions are going to contain? I'm not aware that anyone's agreed on a definition of gender identity. In the Equalities Act, the protected characteristic is gender reassignment. Even that is a bit vague within the bill, to be perfectly honest, but the trans and gender identity are wider concepts than just gender reassignment. If you want to meet the Equalities Act, then you should be focusing a question on gender reassignment, but if you want to respect the wishes of many LGBTI communities who want their self-identified gender to be recognised in the census, then you would need to ask a wider set of questions. That's why I was saying it's very difficult, it's such a complex area, it's very difficult to squash it down into one question about sex and another question about trans or gender identity or something else. Unfortunately, I don't think there is yet a consensus on what is meant by gender identity. There's possibly more of a consensus around what people identify with as trans, but that's broader than gender reassignment. It's a tricky terrain in definitional terms. I'm going back to the issue of the 2011 census guidance and the issue of self-identification. It has been suggested by some that, in light of the fact that it is almost certainly the cohort of people here who may have followed that guidance and then answered the mandatory sex question accordingly, would be quite difficult. It's quite small that, statistically, it's not going to make much difference to the accuracy of the data. That was an argument that has been put forward. It would be interesting to hear your comments on that argument. In 2011 versus 2021 is a big issue. What happened in 2011, we can't tell, although Susan says, if we got really good, clear questions in this census, we could go back and quantify in a better way. 2021 is a very unknown. I think that I would be very reluctant that numbers would be small than 2021, taking advantage of the ability to identify other than your birth certificate sex. We just don't know. What we do know is that this is a growing phenomenon. That's why it's coming forward now, is that the numbers of people presenting in the most formal sense—so that's to gender reassignment and gender identity clinics—is going up really, really fast. That's only one part of the transpopulation. Not all of them will engage with those services. It's a huge unknown, I think, is what you introduce into the data. If you simply add extra category, you don't know how many people will use it, and you can't do much if you simply do it on the gender identity conflation basis. I can't then do much to do all the things Susan was describing so clearly about trying to disentangle all the characteristics of a person, so you can really know about them. I think that's the issue with trying to say the numbers will be small in 2021. I don't think there's any basis for saying that. One of the other issues, I work largely on data around higher education and education. It's not just about the aggregate numbers in the population that you need to think about. You need to think about where it might be concentrated. For the data that I use, which is a lot about people in full-time education in their teens and in their 20s, if the phenomenon of taking advantage of a gender identity flexibility in the question was particularly concentrated in that subgroup, the data effects would be, obviously, much more concentrated in that subgroup. It's very unlikely that it's going to affect people 50-plus. That data is largely likely to be... I would guess that it will be a minimal effect, but as you go down the population, it could change. That's quite important for me as a data user that the effects could be very unequal in ways that really mattered. Interesting. Any other comments? Yes, I would agree with that. We think that there are small numbers, but until we actually have measured in the census, we don't know how small or large that number is. You're absolutely right. A population at a macro level probably won't make an awful lot of difference. The purpose of the census is not just for macro-level population analysis, it's for micro-level analysis as well. That's why we collect such detailed information about individuals and about households. When it comes to things like looking at vulnerable populations, marginalised populations, those often are very small. If we don't have data, accurate data on those groups, then we're not able to tell how badly discriminated against they are. If you look at health conditions, if we want to look at things like... Trans women will still have a risk of having prostate cancer, for example. If we don't properly understand the relationship between sex and gender identity, we won't be able to analyse whether trans women and cis men are more or less likely to have those sorts of conditions. Trans men, I still have probably a higher risk of breast cancer compared to cis men because they are biologically women. If we don't collect that level of information, then we can't properly understand what risks certain groups within the population face. There is another point that comes back to the question about sex and whether we should have this other category. I'm concerned that people will not answer the sex question. Again, I would come back to a public campaign around why it's important to ask that question.  If their objection to self-defining as male or female is problematic, then I should think that their objection to being assigned a sex that they haven't decided on is probably greater. I thought that you wanted to come in. Is that okay? Yes, I have. Just to make a couple of points, the census is clearly the most comprehensive data source that we have for populations every 10 years. I think that committee members should be aware that it's not without its issues. Obviously, we're moving away from the face-to-face collection of the data. We're not sure what impact that will have on response rates and the accuracy of the responses. We know that there's budgetary pressures and other pressures to move the census further away from that and perhaps even to move towards a sampling approach, all of which will reduce the quality of the data, even at present. Notwithstanding that census is the best source that we have, there is still a response rate. 100 per cent of the population do not respond to the census. We already have statistical uncertainty around some aspects of it. There have been some census years where there have been huge problems. Famously, in 1991, around the time of the poll tax dispute, there was a very large non-response because people were fearful of being caught up in that dispute. As a result, a large number of people had to be imputed into the dataset in order to balance up what we thought was a missing population in 1991. There are problems with the census as it is, but we should steer clear from thinking that the census is accurate down to 0.001 per cent on every parameter that we collect. I would also like to raise, if I may, a point that was being made last week in evidence that we took and just to hear your comments on this. A point was made that, whilst it was recognised by this particular individual that the sex question was massively important for things such as health planning, they went on to say that sex is only a proxy for making decisions about sex-specific services. Then they went on to give the example that not all females need cervical screening because they might have had a hysterectomy. We cannot tell whether someone will automatically need cervical screening just by knowing that they are female. That was the point that was being made to support the view that that person was taking last week. I would be interesting to hear your views because we have already heard from Professor McBee, for example, that the use of the data goes much wider than simply for health purposes. Even if we just take health purposes and go back to the mandatory sex question being potentially sex at birth or sex on the birth certificate to deal with the legal sex definition, I would have thought as a woman that there would be many, many other potential health implications for taking the box female, whether or not you have had a hysterectomy or not. There will be many other issues. Am I wrong in that thinking? For individual healthcare services, most of that will be run through the community health index, the CHI data set, which is the collation of all your health records, whether it is your GP records, your prescription records, your hospital admissions. That is the system that is used for the screening services for identifying needs. In relation to the trans community, the variety of healthcare needs within that very broad spectrum of a community will vary widely. The best way of identifying needs is not through the census, the best way of identifying those kinds of needs is through existing health records. If that is an example that has been given, whether or not a woman has had a hysterectomy, that is one element of their health history, but there would be many other issues pertaining to your sex as a female beyond simply a hysterectomy and cervical screening, surely. To me, that argument did not seem to be compelling to me to put it that way. It was just really to hear from your data statisticians what you felt about it. It was back to whether we are thinking about individual need or population level need and the two can't be conflated. As a woman, your needs will be varying on a whole variety of different characteristics. Beyond whether simply you still require cervical screening or you've had hysterectomy, there may well be other issues of progress. We've mentioned breast cancer for being one. All true, but you wouldn't identify any of that. You wouldn't identify people's needs through the census for any of that. You would identify that through your health records. One last question for me. I know that others will probably want to go back onto this territory, but I was just interested in the process of the census and at the moment, leaving to one side the face-to-face or whatever, but at the moment it's per household. Concerns have been raised about people's privacy and questions that they may feel are intrusive, notwithstanding the confidential process, but they may feel are nonetheless intrusive. I just wondered what were the reasons for the census being carried out on a household basis and would there be any argument now, given that the questions are becoming a bit more personal at least as far as people's perceptions are concerned, to have it carried out on an individual basis? The interesting things that are being explored is the capacity to give people an individual form. In the coming census in 2021, people can apply for an individual form so they don't have to have their data provided as a household thing. That's seen and this is part of the debate around this, but probably other questions too and privacy and issues which I'm not a historian of the census, but if you go back to 1901, you're talking about a world in which the part of familiar fills in the family form. We have moved on a great deal from there and you see that in the planning, so I think one of the things that Susan mentioned was what kind of publicity, what kind of public information happens around the census in 2021. This will be one of the things that will be very important to make clear to people who for whatever reason have any aspect of their data they do not wish to have reported for them. That's something that the NRS says that they are going to test further, how they're going to run that part of it, so I think it's important to notice how we're changing there. That's a really important point. It wasn't clear to me reading the briefing documents to what extent the piloting of various sensitive questions had been done with respect to how you would complete them in different circumstances. Certainly that has been a big issue in household surveys and that indeed is a large part of why the National Sexual Attitudes and Lifestyle Survey has sampled individuals within households precisely to avoid that. It is certainly the case that there be many circumstances where it would be potentially particularly difficult to answer those questions and perhaps difficult not to be part of the household response, which I think is a really key point. By not being part of that, you disclose that you are not part of that, so I think that needs really careful consideration. It will probably affect a small minority of people, but that will be an important thing to get right. Can I just make a small point on that? All of what has been said is true, but one of the risks of moving towards an individual response is the response rate. It's a balancing act, so if you're trying to capture classically the teenagers or whoever who are not around when you're trying to collect the census data, you could just fail to get them. That's a huge problem for voluntary surveys. It's also a problem for census. It's just that it's less of a problem because of the obligatory nature of it. The more barriers you put in place to collect the data, the poorer the quality of the data will be, and there will be a balance about whether you get the best available data from one member of the household, or you collect individual-level data on the full knowledge that you're not going to get as much of a response rate as you would otherwise get. I can see that that would be a balancing act, but obviously people's rights to privacy is very fundamental. As Professor McVie has indicated in the general sense that there can be a wide-ranging information and take-up campaign, presumably to have people complete the census on an individual basis. I've been one part of the balancing act. Cost is another balancing factor in here. I'm not really that much in agreement with Annabelle on this particular issue because I do think that, as Dr McCartney said, there's a real issue about missing out large numbers of people. I think that we've been discussing on this committee last week and this week about the sex question, but it's really irrelevant if you don't actually get a hold of the person in the first place. I think that the number one priority has to be an accurate population census, firstly, and other things are secondary to that. I don't know if panel would think about that. I think that it's important to note that they are still proposing that it would be a household form, so they're not moving the census across to a wholly individual basis. My understanding is that it would be a very interesting point to pursue with the Government witnesses, but my understanding is that it's still basically the household survey, but you can request an individual form. So the question would be, the one you're raising, is how far will that create the problems that Jerry is saying that you might start having a lot of loss. But in order to come out of the household, you do have to request the individual form, so we're not sending out five million separate forms. So I presume that's the balancing act, and as Jerry said, this is all about balancing. That's the balancing act that the NRS is hoping will produce the right combination of coverage yet some protection for those people who are really uncomfortable with having a household return. People can request their own if you want. That's my understanding. Alexander Stewart. Good morning, thank you. You've talked about making sure we get this accurate information and the accurate data, and that's vitally important because organisations, especially in the public sector, need to think about how they prevent and provide services to make sure this all happens. But do you think that there is a good meaningful understanding of the terminology around gender identity that can capture that meaningful data in the first place, and then when that is a really captured, how that can be used for public authorities to ensure that they manage their equalities effectively, to ensure that they are providing the services that are required? I think it's something that's, I mean, there have been, not in census setting, but there have been many, many data collections of this kind. I think generally, obviously they do the sort of piloting that Ipsos Moray will do. I think for various age groups, for various cultural groups, there will need to be quite, potentially there might need to be quite a lot of explanation, probably more than is needed for if one were to want to justify biological or legal sex. Nevertheless, there are many studies that have provided good quality data, and I think there's a great resource to build on in that respect. Anybody else? For me it's just about having transparency and clarity in terms of the question, and it's about looking at the users of the census and what information they need. So do they need to know simply that someone self-identifies as trans, yes or no, or do they need to know more detail than that about whether someone self-identifies as a man, even though there is cis women, or where is cis women, or alternatively, there are all sorts of other gender identities such as gender neutral and gender fluid. So how much granularity do the users need, and I think that that's balanced up against how much personal information do the people from those communities really want to give in a census. It's about what the benefits are. The benefits of the census are that it enables us to see what the broad characteristics of our population are. It allows us to plan and to target resources. It allows us to do fantastic research. Scotland really is at the forefront of some amazing research based on administrative data, which is linked to our census. Identify what the benefits are and what level of information we need in order for users to use the information to benefit the population, and go no further than that would be my advice. The level of detail you're going to get and would want to get from the census is fairly limited, but there will also be things like the next sexual attitudes and lifestyle survey, which will allow you to make well founded inferences about those populations and what the distributions are within them. So I think the census is part of the picture, not the whole of the picture. That's exactly the case. It's one of the factors that can be used to understand and support individuals across the spectrum about where they can identify and how they then can fit into that process and how organisations can then fit round them to ensure that they have that support mechanism and they have the confidence in doing that to ensure that the information that you get is correct for them going forward. So I think that by doing all of that, it will help identify so many things, but there will always be individuals who are fearful of giving that information because it may be misconstrued or it may be looked on in a different view. I mean, how do you think we're going to manage to try and get everybody to do that? Because without the complete accurate information, then you're only having a snapshot? Not, but you're going to get very useful information. One thing that was said when the first sexual attitudes and lifestyle survey came in is that you won't get useful stuff at all, people will not make it up. That is clearly not the case. You get good, useful information on things that there may be no final answer to in some cases. So in terms of thinking about small population groups and the utility of the data, one of the really important uses is to look at different questions across the census. For example, knowing whether people with particular characteristics are more or less likely to be in particular occupations, for example. Now, one of the things that we argued for strongly at the last census was having income data to understand whether there were differences in people's income. Now that didn't get through to the final level, but you know, these are the missing kind of things about looking at this sort of intersectional aspects of the population, and that's the kind of information you can only really get from a census where you have a very large sample size and be able to break it down by all of these different characteristics, whether they be protected characteristics or socio-economic factors. Jamie Greene. I just want to explore a couple of questions. I'm just looking at the current census, the 2011 census, and question number two is, what is your sex, male or female? Is it your understanding that people who are currently completed this census completed it on their understanding of how they are doing it? Are they currently living in terms of their current gender identity, or do you think that there was a perception that this was a question around their legal status or their biological sex? As Susan said earlier, one of the problems is that we can't at the moment tell how people read that question. What we do, the best evidence we have maybe is actually from the sex and gender topic report that accompanies this piece of work, which has some very interesting and quite rich data set of interviews with trans people who had filled in a pilot set of questions, including a binary sex question and comparing that with other questions. What was interesting to me reading that was that within that group there was a very mixed reaction to what the question meant, and that was a question that was pretty much like the one on the 2011 census. So I think there is some indication from the topic report that at least some people who identify as trans will have read that question as a biological sex question. But we can't tell—actually, I've been very taken with Susan's point—that if we get a really good set of questions in this census that are very clear, we can backtrack and we can find out. But until we do that, it's really very difficult to judge how that question will have been read. For most of the population it will have been a very straightforward ticking of the box, but for the group we're interested in here, it's unknowable what proportion read it in one way and what proportion read it in another. Perhaps before others respond, if you want to, I might ask a further question. Can I ask the panel what sort of data should we be collecting? Because surely at the core of all this is what is the purpose of the census? What sort of data do you need to be collecting? The previous census asked all sorts of weird and wonderful questions about how people travel to work or whether they've been looking for a job. So really it's about working out how important sex data is or how important gender identity data is or sexuality data is. Does the panel have a view on what sort of data should be collecting which therefore will define what sort of questions you need to be asking people? OK, I'll have a go. You start with the Equalities Act and you should be collecting data on sex. So whether you define that as biological sex or legal sex, that's essentially a matter for debate. It won't make that much difference to the numbers.  I think there are already a good set of well tested questions around sexual orientation. So I don't think that that's particularly problematic. Then you've got gender reassignment which is the protected characteristic. Now I think the Equalities Act is not entirely clear what it means by that. The actual description of gender reassignment and then some of the examples that it gives if you look in detail at the content of the act is a bit blurry. However, there are a number of surveys that have looked at issues around gender and gender identity and I think we should be going to the tried and tested surveys that have identified good questions that have had cognitive testing to ensure that people understand what they mean and that they have relevance and validity to those individuals. So I'm not going to give you a set of questions but I think that we're not starting from scratch here. I mean I think Jackie probably knows more. I mean I'd agree with all that and I think specifically with regard to the trans question I think it will be quite important to think what sort of dissonance from either biological legal sex that might mean. Because clearly there is a very strong sense which I think is accepted in the plans that there are people for whom that dissonance is problematic. It's not at all clear to me who will answer that is yes and I think it needs to be really thought about what is it that we need to know about what range of people who may or may not use the trans category beyond gender reassignment. I think that that's really difficult and it's not sorted but it's really important. If we want to have a population statistic for trans then you ask a question about trans yes or no. I think you should possibly also give people the opportunity to say what they feel there, how they would self-define their gender identity. Some people will prefer not to say that but many people. I think that we wouldn't be sitting round this table if there wasn't a demand from the LGBTQI community to see that the sense is better reflects the characteristics of our population. I think that it's giving people on a voluntary basis the opportunity to self-identify in the way that they wish but not imposing a set of questions on anyone and at any rate that's not mandatory. I think that the question about gender reassignment is a more tricky one because it is a protected characteristic so therefore we should be collecting that possibly as a mandatory question. That's going to be my follow-up actually to that. Which of these questions should be mandatory because it's an important date for government to collect which should be voluntary. In that respect it sounds to me like there is still debate around whether the collection of both legal and biological sex would still be useful also because as others have mentioned that would have for example some medical benefits of knowing someone's biological birth sex versus how they are currently defined in the law for reasons of diagnosis of certain conditions etc as was discussed. So which of these questions do you think we must know and which do you think people should be allowed to answer in their own way regardless of what that question is. I don't think we need to define that question and my final point is around whether the panel has any views on if the method of collection of the status will change next time around. IEP we don't have to give face to face answers door step. Would you expect people to be perhaps more honest and open about their answers or do you think there may even be some disproportionate levels of responses from certain communities in regards to the census. Can I just say I think one of the reasons I would strongly support voluntary responses to these questions is it is clear that not all of these questions and as the guidance discusses are meaningful to all people.   I think that that may well be true for that's likely to be true for trans to it and where so where there's a problem with the what not a problem but where something is not universally felt to be a category that might usefully apply then I think it's not clear that how you could or should make that a compulsory question quite a part of all the wider issues about privacy. Your question is more broad but you're saying you're not suggesting that the sex question should be voluntary? I don't think that the sex question should be voluntary and I think the issue of what it is that one is wishing to have really robust data on through the sex question so I think the sex question should be voluntary but I can't see. The sex question should not be voluntary but the sexual orientation and trans questions I would say should be voluntary for various reasons. On the sex question you're talking about biological and legal sex it's likely that the terms which are somewhat legal sex have got contested I think as to what is which so the way I would like to characterise it is are you looking at your original birth certificate sex or your current birth certificate sex because I don't think there's any dispute beyond the fact that it's one of those two which tends to come up as a legal definition of sex you're looking at one thing or the other and I think that's really the main issue that's going to be in terms of the sex question is which are those two. I'd like to refer about Tim Hopkins made a point which I'd really like I think the committee needs to give careful thought to accept an important point about privacy rights under the European Convention on Article 8 and how far that might bite on the census and the sex question on the census and I think that's not something that the Scottish Government that the policy memorandum talks about but the issue about whether and I think my understanding is we're talking about GRC holders who have changed their birth certificate. I think that there is a substantial point that's worth teasing out a bit more with the government about whether they think actual legal privacy rights at that level kick in for that small group of people and I think I would want to put on the record that as far as I can see as a data user the decision that's made there is you could you could go either way and it wouldn't affect the data that the committee the decision to collect current birth certificate sex rather than original birth certificate sex affects such a small number of people and we know a bit about them because we have a register so we know what age they are we know you know we they're not an unknown group that it is a decision that shouldn't you don't need to worry about the data quality impact of which of those two you go for and I would be interested I think just to know that if that's a view shared. Odding there Professor McVay. Yes absolutely I mean personally if it was a choice I would go for legal sex which means biological or whatever's on your birth certificate but I think there's a wider group of people for whom their gender identity is more fluid or not necessarily it's not confused but it's less clear and that's why it's difficult to have a set of questions that fit everybody because trans is used as a kind of umbrella term to describe a community but there are many within that community that don't necessarily feel that they're the same as others within the same community if you see what I mean. Some will have had surgery and others will not. Yes or at various stages of medical treatment others decide that they don't want or they don't require to have any kind of medical intervention whatsoever. Jamie Greene have you finished your line of work? Yes just to start a final point around the way that we collect the data if that changes and it changes the method to digital or postal or what have you. Will that affect the data and perhaps some even question from Mr McCartney as well in the sense that if you're asking these types of new questions will that encourage certain communities to want to answer those questions and therefore the proportionate percentage of that data set would be disproportionate to what you would normally get under a different collection method. I'm sorry if that's a convoluted way of explaining what I'm trying to say. Sorry, I'll just, so there's two points here. One is will changing the mode of delivery change the response to the survey and at the same time will asking a new question which is quite sensitive question change people's likelihood to answer that question and will that be influenced by the mode of delivery. So it's quite a complicated circumstance because you're changing two things at once so trying to test the effect of the changing mode of delivery on the response to the question is difficult because you haven't got anything to compare it to. What we can compare is I suppose the level of response to those who complete the paper questionnaire in the traditional way to the level of response to the people who complete it using the electronic form. We know because we have tested in survey design we have tested asking sensitive questions using non face to face methods and it does tend to produce a greater rate of response. So in the Scottish crime survey for example back in the 2004 I think we tested a telephone survey to collect the data on victimisation. Now it was a terrible, it was a disaster because actually what happened is that people that hadn't been victims of crime just said it's not appropriate to me so they put the phone down. But people that wanted to respond about crime participated and we had something like if I remember correctly 150,000 percentage increase in responses to questions around sexual assault for example because people were much more likely to respond if they weren't being asked those questions directly face to face. So there are other examples where electronic means make people more likely to feel comfortable about responding but the overall change in the mode of response I think Jerry said very clearly that it's a risk changing from face to face delivery to electronic. You will have a percentage of the population that will always complete a survey, it doesn't matter how, what form it comes to you, you'll have a percentage that probably never will and it's the ones in the middle. So the question is to what extent will we have to do more work to persuade the ones in the middle to participate. I want to come in. The Scotland is not the only country that will have a census. Do you have any international comparisons in terms of the type of question or question that should be or could be asked and I'd assume that this debate will be taking place in other countries as well. I'm sorry I don't know enough about the census in other countries to answer that question. The only thing I could add is just that I know that national records of Scotland have been working quite closely with the other agencies across the UK just to work together and sharing costs around the investigation of different questions and sharing the costs of research. So I suspect that questions across the census in the UK will be quite similar both for comparative purposes but also just because the process has been quite similar but I'm not sure beyond that. There are some very large scale demographic and family surveys across the world, some of which do ask fairly detailed questions because there's so few other data but I think the census here needs to see it within the context of very good health data particularly in Scotland. Excuse me, I think I might excuse myself. I'm fine, thank you. That's okay. Sorry, Kenny Gibson. In a supplementary submission to what she gave in her robust evidence last week, Professor Rosa Friedman said and I quote, There is little supporting evidence for a genetic or anatomical brain basis for being born in the wrong body. This idea now is currency with the public and it appears that they believe it is medically injurious to the public. There is little supporting evidence for a genetic or anatomical brain basis for being born in the wrong body. This idea now is currency with the public and it appears that they believe it is medically endorsed. Self-identification could lead to a neglect of the proper formal exploration of the wider reasons I personally want to transition. These are often unconscious and need time to emerge and they want to say that we believe usual standards of evidence should apply based on the National Institute of Excellence in Health and Social Care so that interventions would prove mortality or quality of life. I'm just wondering if you can comment on these submissions these years. How do you feel about them? In terms of their relevance to the bill. The reason why they're relevant to the bill is because what they are saying in their evidence is that if we don't actually get proper accurate information about the individual's concern then we may actually take their own decisions in terms of interventions now. Earlier on, Lucy Hunter-Blackburn and you said that Professor Jacqui Cassel agreed that the numbers are small so therefore you don't believe they would really have any impact on how we actually look at interventions but you also said that the numbers of people who are reporting to be transgenders is increasing rapidly at the same time. I'm just wondering if, in fact, there is something in the two professors and two doctors that are actually saying in this. In terms of the legal definition, I think that Rosa Freeman was particularly interested in the legal definition of sex and that takes us back to the discussion of are you looking at birth certificates and if so which ones. That's a relatively narrow point whereas I think the broader question about trans identity is we keep coming back to the same point which is that it's a very various group and getting the right set of the right bank of questions which has something about your unambiguous sex status whether it's tested by one type of birth certificate or another but then on top of that measures the other dimensions of how you identify yourself. It's getting that whole bank of questions is what gives the sort of information that I think if I hear that rightly is what's wanted and what's needed so it's about the layers of information we collect and not neglecting any one of those layers because we're dealing with it with a very fast and I think it's true a very sort of fast moving and shifting thing but even by 2021 the language and what's acceptable in the terminology we can't be sure we know. Why that's going to play out so I think when you put that contribution together with Professor Friedman so you're looking at just being very clear about the different types and separating the types of information you're collecting and it comes back to the point that I think we've come back to a few times which is what are those supplementary questions what clarity about the sex question and then what is the nature of the supplementary questions that you'll do the best job for this particular community. Within the constraints of a consensus which is not designed to give a comprehensive account of people in detail. Can I just reflect on I think one of the comments you've been related to is which is in relation to the evidence base around interventions and what have you. So I just want to reiterate that the census data will not be used to plan services for individual people so the best source of that remains within the health service so in a sense that this is a that's an irrelevant comment in relation to the census because you know even if we get the questions perfect on. Trans status on your biological sex on all of these different aspects that people have been discussing this morning that tells you very little about the needs of individuals within health services. No I mean you said that earlier on action I think everyone's taken that on board I mean I certainly have I mean I'm just trying to give you the perspective that these individuals have basically the you know in relation to what they feel is that overall medical services may not be designed appropriately if for example we're not asking the right kind of questions in this. Census and I think they're looking for you know questions that are more sex specific if you like rather than kind of more gender identification because they think that evening that well we won't you wouldn't be designing service on an individual basis even on a collective basis that we might not quite get it right. Clearly the more clarity we can get in the set of questions so that we're clear what how we can interpret those data the better but that's only going to ever be part of the the battery of evidence that we've got. I mean I would agree with Jerry I think the more clarity we have the better but the census is not a survey so you know there are limitations to what you can include in terms of people's background characteristics in the census. The census is intended to be a kind of broad description of the characteristics of the population that we can then link to other data sets such as the health data sets that Jerry talked about. Sex is only sex is only one of a number of questions that are used to link those data sets but having sex in the data is very very important. The other supplementary information we collect around gender identity I think is important for a broader range of reasons not just to look at patterns of health service so you wouldn't use it to plan health services but you would use it to identify for example whether people from the trans community take up services to the extent that people from the cis community do or whether people are discriminated against within certain services the criminal justice system for example by linking lots of administrative data sets together we can test all those things. I agree with what the panel is saying but I am looking to see is would there for example be a possibility that in terms of this would there be a clustering an opportunity to identify with our clusters so for example it may be that people with certain characteristics are identified in some geographic locations might mean that in one area say Edinburgh there may be a requirement for specific services as a result of that and other areas there might not be. That's true so it's easier to imagine it almost with age so if you've got a more elderly population you'll know that perhaps dementia services need to be more advanced in one area compared to another and the same may be true for other characteristics. Can I come back in on this very important point that Lucy Hunter-Blackburn raised about Tim Hopkins point about the privacy of people with a gender recognition certificate and how something that was important for the Scottish Government to bear in mind. Professor McVay you suggested that that definition of legal sex and I think whatever the lawyers seem to be in this debate there's an understanding that a GRC confers legal sex and you said that you didn't think it would make a difference to the data because I understand that only 5,000 people across the whole of the UK have a GRC so it must be very small so understand your point about it not affecting the data. However there are moves to change the way, you'll be aware that there are moves to change the way people obtain a GRC and it's been suggested that there may be in Scotland or the UK a means of self-identification so by the time that we have this census in 2021 it could well be that people can self-identify and get a GRC. And in the submission, the late submission from the clinicians being Buley Clifford apartment that's already been referred to they do say the number of individuals requesting medical assistance for gender uncertainty or dysphoria is rising and the demographic trend is rapidly changing so if by 2021 we had a situation where many more people could self-identify and obtain a GRC and would that affect the data? I think again it comes down to being very clear about what it is that we want to measure.  From a research point of view, if people are registered and there are registers of who has gone through this process then you can connect that data to the census so that you can control for that when you're doing research. The problem is when you have people that self-define and it's much broader and we don't have any measure of how many people are in that community. As long as there is whatever the process is if that process is understood it can be not perfectly but it can be taken into account because if you don't know what the process is which is like to the case if one simply adds in a trans question which is fine then one will not know what that represents and therefore you won't, if you do know what the process is it won't matter actually to accept because you will know what it is that you're measuring. You might then make different choices next time round about what else you need but that's… You know what you're measuring because how would you know if somebody has a GRC and they just say that they just tick the male or female box how would you know that they were… You would know at population level. I mean this is the point about it's not used to deliver services at an individual level so if you know how many people have gone through that process and their age characteristics and so on and what that process consists of… But you're not asking them that in the census though? No, no you're not but we do know that there is this number of people who's gone through roughly this sort of process and that allows you to deal with the data in slightly different ways. It's where you don't know how people came to have that characteristic that it becomes problematic in terms of interpretation of the data. I think it's the difference between where we were in 2011, where we have no purchase at all on how people departed from biological sex. We've got nothing we can check it against and that's where we can work back from a later census to one where we say well we know there are exiles and people who've got a GRC so we've got this many people saying that their birth certificate says at the moment they're male and this many saying female we can make a good quality estimation of the impact on the total data of changes in birth certificates. Where it starts I think where it gets more problematic because obviously what we do a lot with the census is we bring characteristics together and it gets a bit more complicated as you start to look at say in my area where I'm interested in the relationship between education level earnings and sex where we have a very clear thing to measure which is about how that varies over time. Now if there's a concentration of people taking changing their birth certificate in a particular subpopulation it starts to have you have to start imputing quite hard. The word that Susan used you have to start guessing backwards a bit by individual case and that's not ideal but it is better than pure self identification which has no reference point outside itself. So it's true convener that at the moment you can say with real confidence that the scale of GRC holding is so small that you wouldn't worry about trying to impute anything at the current level. If we turn around in 2021 and there'd been a legal change and because the process if they follow the process that was being put forward it's a very quick one. So it was brought into force in time for the 2021 census it's feasible you could have thousands of people who are very keen to change their birth certificate taking advantage of it before the census. It's true that it could have an impact for 2021 but I would worry much less about that than I would about staying where we are as was used in 2011 which has a much less manageable much less estimatable effect. It's about known unknowns and unknown unknowns so people actually are registered somewhere even though they use if the definition is legal sex but they're registered somewhere then that's a known unknown so we don't know exactly in the census whether they are on the register or not but we know that information from elsewhere and actually through data linkage we can link those data sets together so we could actually link the census data to the register data if that data was made available for data linkage which increasingly everything is. I mean we now have vast majority of the health data, we have crime data, we have education data, we will shortly hopefully have DWP data so increasingly we are constructing what we see in the Nordic countries as standard which is all of the public sector data linked together so we have a much better understanding of how everything links together but the problem is when you have unknown unknowns which is the kind of the trans community is not defined in any kind of way so we don't know who belongs to it so we have a kind of vague ambiguous question in the census and we don't know what the extent of the population is elsewhere then we have no way of estimating the scale of any problem of bias or discrimination or inequality for example. You seem to be as one on that particular point however what is said in the explanatory notes for the bill is that the Scottish Government already conflates sex and gender and it's very clear from some of the public authorities who have, we haven't had that many submissions from public authorities but those that we have I can think of at least one that clearly didn't understand the protected characteristics of the difference between sex and gender and even the equality impact assessment for this bill conflates sex and gender reassignment so clearly right across government and public authorities there is a lack of clarity on this issue which you are saying is an unknown and that's actually a problem in terms of the gathering of data so I know that you are on the board of Scottish statistics I believe Are you concerned about this kind of creep in these attitudes in terms of gathering statistics? Yes, yes absolutely. I mean we know that we have many administrative data sets that don't necessarily use the same definitions for things which is why it's so important to get it right in the census and why this could be a really important model for all of our other public sector data sets that we should have. That we should harmonise on these questions if they don't and if these things are being conflated then there are issues around the Equalities Act. I think it's essentially there's been a fudge over time and this is the point at which to do something about it and the NRS through this work with the census could really be shining a light for all other organisations. Having said that it is important to recognise that many administrative data sets that are used by public sector organisations for example are not collected as measures of the population. They are collected as management tools that enable them to do a good job so it's not always as important that they have a clear distinction between sex and gender identity because actually the purpose of them is to deliver a service to individuals. For that purpose it's not always as important however I do think that people should be clear when they're talking about sex and gender identity that they're two very different things and I think as a society we have not been good about defining those two things. I think that people have had a problem of using the word sex to define biological sex because it's connected to other forms of behaviour so therefore as a society we've been lazy intended to use the word gender when what we mean is sex. You see that in the documents all the time that goes from one to the other. Claire, did you want to come back in? Yes, just briefly. I mean this committee has given this bill a fair level of scrutiny but do you feel that the NRS in terms of consulting on this census and the previous census where the guidance which many panel members have suggested was problematic was published. I mean I was struck by Susan McVie saying that as a body you weren't consulted on the 2011 and there seems to be a feeling that the 2011 question on sex that went ahead without a little or was there a discussion where you as a... I wasn't part of a group that was or wasn't consulted. I mean my point about 2011 was really just the design of the question. Who did discuss the design of the question? Do you think that the consultation process that NRS has is broad enough to collect sufficient views for the make decisions on these areas? One of the things about 2011 is we just don't know what the process was behind the construction of the guidance so it wasn't the question because it was the guidance that went with it. Nothing has been said and I don't know what was done. It's a question to explore perhaps with them what the process was in 2011 that led them to this quite major change really in conceptualising sex. It doesn't seem to have been subject to well certainly parliamentary scrutiny but that it's not clear what scrutiny it was subject to outside NRS. In terms of the current process the topic reports a fascinating read and has lots of great information about the cognitive testing and quantitative testing of questions but it left me as a reader with quite a lot of questions about how the decision process stage by one decision had been taken and another hadn't. So there's a very strong statement at the start of the topic report on page 3 about the importance of sex as a marker and the equality act and elsewhere. But then almost immediately it says and what we want to do is interpret sex as self-identification and there's a jump from one to the other that really isn't explained in the document or in the policy memorandum either. And then as you go through the topic report I had similar questions so for example if you felt very very strongly that you must give people a chance not to provide their sex detail that it was too distressing for some respondents to provide their birth certificate sex. Why not offer a prefer not to say answer? Why move to a third sex option and that in fact one of the trans respondents whose comments are taken upstairs as we could have a non-response issue. So there's a whole reading the process behind this I was struggling a bit to understand why certain at various forks in the road why one fork had been taken and not another. And particularly underlying that though is the why NRS seemed to be taking quite a strong view in principle that sex should be regarded as a self-identification issue. And I don't find a clear explanation for that and how far that's explained by who they spoken to and the processes is I think a thing you'd need to explore directly with them. I mean you know going forward then if the NRS was to change its approach to working with a wider set of people would you be willing to work with them to look at the user community then yes absolutely. We shall pass that on. Can I thank our witnesses today for coming along to give evidence to us. It's been very helpful and I'll now move into private session thank you.


Hello, this video is the last part of a series on practical RF impedance matching and filtering of the STM32WL. In this part, we focus on the Receiver Matching Network and Balloon. As mentioned in the first part of this series, there are several ways how to do this task that differ in complexity. In this example, we show the simplest method based on a reusing an existing STM32WL design. It should be enough for most of designs. The main steps of this method are Using the reference layout of the Receiver section as much as possible Using Receiver Component Values as in the reference design The Component Values can be fine-tuned if needed. Fine-tuning may be needed due to differences in the layout, RF switch, component types, etc. Fine-tuning is based on measurement of Receiver Sensitivity, Receiver Standing Wave Ratio and Current Consumption. These points are described in more detail in the following slides. There are several designs which can be reused. Some examples are here. Each board has a bit different configuration. There are boards for BGA or QFN package for two or four layers, etc. The Receiver Component Values were tuned for each particular board. The Values can be reused as initial values and the new design. Design files and BOM can be downloaded on st.com. In this example, we use STN32WL nuclear board. Here is the schematic of the Receiver part of the STN32WL nuclear board. We can see Balloon Light and Matching Network, the RF switch and the DC block, the Antenna Matching Network and the SMA connector. The Balloon Light circuit transforms the single-ended signal to differential. As we mentioned in the previous part of this series, strong harmonics from the transmitter may couple to the Receiver part through the PCB. This capacitor can help attenuate these harmonics. The recommended values for the Receiver part on this board are as follows. We use these values on the original board, so fine-tuning is not needed. The Antenna Matching Network uses the values that we calculated in the previous section about the transmitter. The PCB layout of the Receiver path looks like this. We can see differential inputs of the Receiver and differential transmission line, Balloon Light and Matching Network, capacitor which can attenuate coupled harmonics from the transmitter part, RF switch, DC block, Antenna Matching Network and the SMA connector. Impedance of the single-ended RF line is 50 ohms. Impedance of the differential RF line is 100 ohms. Length of the differential RF line has impact to the Balloon Light components. If the length is different, the values may need to be fine-tuned. In this picture is highlighted the Receiver path on the tested board. From differential pins through the Balloon Light circuit, RF switch and the Antenna Matching to the SMA connector. The AT Slave can be used also for testing of the Receiver. During the measurement, we need to set the RF switch to the Receiver mode and set the STM32WL to the Receiver mode as well. Here are the commands which can be used. For configuration, we can use the same command as we use for the transmitter. For sensitivity measurements, we need to set parameters of the modulated signal. If we want to only turn on the Receiver, no special setting is needed. We can use default values. The ATTRX command switches the STM32WL into the Receiving mode. The parameter is number of packets, which will be received. This parameter is used for calculation of the packet error rate. Here is the example of this command. 10 packets were being received. There was noted signal on the SMA, so the calculated packet error rate is 100%. The most important measurement is the Receiver sensitivity measurement. Good Receiver sensitivity means that the button light circuit and the matching are set correctly. The Receiver sensitivity depends on the modulation and its parameters. The datasheet specifies some sensitivities. They can be used as references for other measurements. Sensitivity measurement is quite complex. The simplified variant of sensitivity measurement is shown in the separated video of this series, which is named as basic RF measurements. On our test board, this sensitivity was measured. Lura modulation with these parameters was used. If we compare this value with the reference one in the datasheet, our Receiver path is set correctly. The standing wave ratio measurement indicates how well is the Receiver path matched. Good value is typically below 1.5. The measurement of the standing wave is quite easy. The vector network analyzer is connected directly to the SMA connector of the board. The STM32WL is set to Receiver mode. The RF input power of the Receiver should be below 0 dBm. In our example, the power from the VNA is minus 30 dBm. Here is measured standing wave ratio of our board. It is around 1.5 dBm in the whole band. The exact values are listed here. The last thing to check is that the current in Receiver mode is within the expected range. Typical currents for some cases are in the datasheet. The main difference is in the SNPS and LDO mode. The variants with boosted receiver have slightly bigger value. On our test board, the current is measured at the same point as we used for the transmitter. It is marked as IRF. Our measured current is about 5.5 mA, which is expected value. The optimum values for a particular design may differ from the values used on the reference boards. In this case, the reference values can be considered as initial values which can be fine-tuned. Maximum values for the particular board are usually around these initial values. This is valid if the Receiver part layout is similar to the reference. Typically, these two capacitors are slightly modified. One sets the matching, the second phase and amplitude of the differential signal. It's recommended to change only one value at a time to see the impact. Changing one capacitor may affect the other, several steps may be needed. After each change, the impact of the change must be verified. The most important is the sensitivity. The standing wave ratio may help with tuning. We can see where the matching is better and where worse. Let's summarize the Receiver part matching. Matching of the receiver may be time-consuming. To speed up the process, the recommended way is to reuse the existing layout and boom of reference boards. The boom values can be used as initial values for new design. These initial values can be fine-tuned if needed. If the PCB layout is similar, the optimum values are usually around the initial values. Typical measurements of the Receiver parts are sensitivity, standing wave ratio and current consumption measurements. Thank you for your attention.


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