Tuesday, October 28, 2008

Computer Science AP Test

Harry Lewis went to a meeting about the future of the Computer Science AP Test. He wrote a short report for our faculty, and gave permission for me to put it on the blog. There are a few Harvard localisms in the report, but I think the information is important for everyone to see.

Guest post by Harry Lewis:

Over the weekend I attended a meeting in Chicago about the future of the AP Computer Science test, along with about 70 other faculty and a few high school teachers.

The College Board announced last year that it was dropping the CS AB test after the spring 2009 administration (the more advanced version, with more on data structures and algorithms) for business reasons (only 4000 test takers). The A test isn't that popular either -- 18,000 I think. By way of comparison, 180,000 take Math, 80,000 take Physics B, and 75,000 take the Statistics exam, if I wrote down the numbers accurately.

The CS AB test is the only one for which Harvard gives credit for advanced standing purposes (and then only if you get a 5). I don't think it would be wise for a student who has taken only the CS A course to skip CS50. So as far as I can see, Harvard won't be offering credit for AP CS after this year.

The numbers of students studying AP CS are pretty bad. Only 12% of American high schools even offer a CS AP course (even the A).

There were rumors that some effort going on to line up industrial support to keep the exam alive. (The Italian-American community got their act together when the College Board cancelled the AP Italian exam, and managed to keep it going by pledging to pay the College Board, even though even fewer take it than the CS AB test.)

The economics of this are interesting. Most of the costs of administering the exams are in grading the free response (non-multiple-choice) questions. But a psychometrician gave an interesting presentation -- it seems that the FR questions contribute nothing to the validity or reliability of the test scores that was not already there in the answers to the multiple choice questions. (Which is not to say that teacher and student behavior might not change if they knew the exam were nothing but multiple choice questions. And the psychometrician cautioned that he hadn't calculated the nontrivial and perhaps different costs of developing the MC and FR questions themselves.) On the other hand, the College Board is probably basing its cancellation judgment on trend lines. CS seems not to be growing in high schools, AP or not. (Whereas Chinese and Japanese, also currently small tests, are.) (The College Board made the decision to drop the AB test and has no plan to reconsider it. It announced its decision without any consultation with the faculty groups involved in developing the exam, by the way.)

A great many people at this meeting don't like the A test, and after taking and grading a few questions, I can see why. It's a Java programming exam. Graders are trained not to take off for trivial syntax errors (confusing commas and semicolons in written answers). They do an incredibly good job developing grading rubrics and keeping the grading consistent between graders. But there are more questions about OO programming concepts than anything else, which doesn't seem right (on the exam we looked at, there were 18 questions on inheritances and whatnot, and 2 on "logic"). Several people said, "if you wonder why kids are turned off on CS in high schools, just look at the questions on the AP exam to see what image of the field is projected." Some proposed, half-seriously, that we ask the College Board to rename the existing course and exam "AP Computer Programming" (no dice, it has to be the name of an academic department in colleges and universities).

There is a movement afoot not to tweak the A exam, but to develop an entirely different kind of intro course to be the basis of the CS AP, something broader, emphasizing both the principles and the importance of the field. A couple of prior working groups drafted proposals. They are right on target IMHO, though maybe better goals for what our majors would understand at the end of 4 years than at the end of the first course. We spent Sunday discussing these. (The College Board is emphatic that there will be only one exam in CS, so this would substitute for the A exam, and we are not discussing a substitute for the AB exam in addition to keeping the A exam.)

These 2 proposals have no operational content at this point. The discussions we had were not premised on there being any programming, or on what programming language might be used (though there certainly seems to be a consensus that the first programming course should use a light-syntax language). And the discussants yesterday were divided on that question. So we are still in early stage development.

We didn't even talk about testing. The two boundary conditions are that the course has to be testable (though not necessarily multiple-choice testable), and has to draw people into the field (the NSF was represented by Jan Cuny, who was evangelical on the subject of drawing more people into the field, especially groups now underrepresented in the field, and has curricular development money to put where her mouth is). Obviously the easiest things to test are programming and math, so this is a nontrivial feasibility issue.

A critical question was whether colleges would give the imagined new AP course credit. I found that hard to answer. With no programming, or very little, it certainly couldn't place people into CS 51 or 61. It seems to be in the CS 1-QR48 space (though maybe not, if there is significant programming after all). Harvard doesn't give Advanced Standing credit for courses that no department would count toward their major, and you can't place out of your Gen Ed requirements on the basis of high school work anyway. In the end I decided there were too many ill-defined variables for me to claim that Harvard would give credit for this course, though I think it has huge potential.

This would take a minimum of 5 years to mature into textbooks, teacher training protocols, etc. Probably more.

There is, by the way, some worry that the College Board's decision will (a) lead to a general dumbing-down of high school CS, marginal as it now is, and (b) deprive us of a small but important part of the flow of new majors (though the number of students taking the AB test nationally is tiny, 40% of them become CS majors, and I'll bet a significant number of our CS majors are in that number).

It will be interesting to see how this develops and there will be opportunities to be involved in the development.


Harry Lewis Tapes an Ad for Darcy Burner

Without trying to be overtly political, I thought I'd mention some "public service" performed by Harry Lewis. Apparently, Darcy Burner, a Harvard alum running for Congress, said in a debate, "I loved economics so much that I got a degree in it from Harvard." The Republican opponents are questioning her truthfulness, since her actual degree is in computer science. Back in the day (as I well know, as the requirements were the same as when I was an undergrad) for the computer science major you were supposed to take several classes in a related field of your choice. Mine was math. Economics was a popular choice, and was apparently Darcy's. This is (by Harvard policy) not noted on the transcript. There is no sign that she has ever attempted to mislead people about her degree; her resume says she has a computer science degree with a specialization in economics, which would be a completely accurate description in my opinion. You can search online for more info.

Harry Lewis publicly backed Darcy Burner's statement, and in fact is now featured in an ad explaining Darcy's academic qualifications. You can read the Crimson article here, and see Harry set the record straight here at Youtube, or here, and probably many other places. Thank you, Harry! No matter what party you favor, certainly everyone is entitled to the facts without the spin, and that is what Harry has provided.

Harry is naturally polite and reserved in his statements, but I'll be more clearly biased: any district should be thrilled to have a Congressperson with a computer science degree, and especially one with a degree from Harvard!

Friday, October 24, 2008

On the Ad Board (A Harvard-centric Post)

The Harvard Crimson had an editorial earlier this week on the Ad Board, the administrative board that implements the rules of the college for undergraduates, and which I served on for a year-and-a-half, ending last June. (I happen to read the Crimson semi-regularly as copies are left in the lounge areas of our building.)

The piece was just so over-the-top negative, and blatantly factually wrong (it's hard to find a stated fact in the text that is actually correct), that it makes this season's political ads look good by comparison. So I took it upon myself to respond.

I suppose only my Harvard readers might care about this, but here's the editorial, and the text of my response is below. We'll see next week if the Crimson publishes it.

UPDATE: The Crimson did print my letter here. (It changed a few things, making it shorter and a bit more generic, but the spirit is there.) Also, since it seems from the comments that many people are simply uninformed, let me point to the Student Guide for the Ad Board; I'd encourage people with questions (or complaints) to read that first, as it gives a lot of detail about how the Ad Board works.


Bad Board, No; Bad Editorial, Yes

To the Crimson editorial staff:

Having finished a year-and-a-half of service as a faculty member of the Ad Board last June, I was shocked by the opinion “Bad Board” that appeared in the Crimson on October 22. First, it was simply riddled with factual errors. For example, contrary to your statement that resident deans are “outranked” by the faculty, in fact there are only two or three faculty members on the Ad Board at any time, and over a dozen resident deans; we all get equal votes. Even if we didn’t take the resident deans seriously as you suggest (and we do), they could simply outvote us. As another example, contrary to your statement, in disciplinary cases students are always allowed to present their side of the story, both in written form and by attending an Ad Board meeting, where students can make a statement and, if they choose, respond to questions. I could go on, but there are so many additional factual errors that it would take a letter much longer than the original editorial to go through them all.

Second, your editorial fundamentally misunderstands the Ad Board’s setup and purpose. You complain that students cannot hire an attorney for an Ad Board hearing. That is because the Ad Board is not a legal institution, like a court or the police, but an academic institution, to administrate the rules of the college. The Ad Board’s purpose is fundamentally education, not punishment. As you quote, the Ad Board is “primarily concerned for the educational and personal growth of undergraduates, both as individuals and as members of the Harvard community.” Sometimes, when a rule is broken, a punishment must be given, but we view that as a learning process for the student. Attorneys should not be a part of that learning process, much in the same way you can’t hire a lawyer to complain about or negotiate for a better grade in my class. (Please don’t try.)

Finally, your article includes what I would call errors not of fact but of spirit. You say “rulings are clear before it [the Ad Board] convenes”. That’s a surprise to me, as I regularly spent multiple hours in these meetings each week listening to and deliberating cases. Punishments are not, as you say, “one-size-fits-all”; we discuss the appropriate response for each case, based on the rules of the Faculty and the needs of the individual student. We take seriously both these rules and these needs, with the goal of best serving both the students that come before us and the larger Harvard community.

I understand that, as you say, going before the Ad Board is intimidating and terrifying for a student. They are generally there because there is an accusation that they have broken a rule of the College, and there may be consequences. I know of no system we could possibly set up where that wouldn’t be intimidating and terrifying. But students should know going in that the Ad Board will listen to them, fairly, and that no punishment is given lightly.

Michael Mitzenmacher '91

Professor of Computer Science

Harvard School of Engineering and Applied Sciences

Thursday, October 23, 2008

PC Members Submitting Papers

I'm currently going through papers for NSDI, and the PC chairs had to send out a post saying how the papers where they are co-authors would be specially handled. NSDI not only allows PC members to submit papers, but the chairs as well!

In the theory community, we generally don't do this. PC members can't submit papers, apparently to avoid any conflict of interest. This is, from what I've seen, unusual, even for CS, which is already unusual in the competitiveness and importance of conferences. Most networking conferences, for instance, allow PC members to submit.

Does conflict of interest really exist in these situations? I don't think so; generally, from what I've seen, it gets handled, and handled appropriately. People on the PC realize it's a competitive process, and understand when their papers aren't accepted. Often when PC members can contribute papers the process is double-blind, so nobody "knows" the PC-authored papers. While I understand allowing PC-authored papers is a risk, I don't think it's much of one. As a comparison point, theory conferences almost never use double-blind reviewing, and I think just the name of a "prestige author" on the paper has a significant effect on the odds of acceptance.

What's the upside? The biggest is that it makes it easier to have larger PCs. I have 20 papers to read for NSDI. I can't remember the last time I had less than 40 papers to review as a PC member for a significant theory conference.

Tuesday, October 21, 2008

Less Busy October

After a few days of trial, the two sides in the case I'm acting as an expert witness on agreed to settle, before any of the experts reached the witness stand. So all of a sudden I'm less busy than I had expected. Maybe I'll have time to whittle down that never-empty to-do list. Or blog. Or maybe a new case will serendipitously come along.

Undoubtedly the people happiest with the settlement are the jury. They were going to have to sit through several weeks of trial, and while I'm sure they were all eager and thrilled to fulfill their civic duty, I'm sure they all have their own to-do lists to deal with.

Friday, October 17, 2008

Busy October (and November, and...)





Those NSF deadlines are looming large.



Guest posters are always welcome....

Monday, October 13, 2008

STOC 2009, Web site + prereg of papers

The STOC 2009 submission page is now up, here. [ https://secure.iacr.org/websubrev/stoc2009/submit/].

While papers are due November 17, you must submit an abstract by November 10. Please pass the word.

For those of you with an interest in such things, we're using Shai Halevi's conference software. I was going to go with easychair, but the one major complaint (that I'm very sympathetic to) was that they didn't allow as a default the use of scorecards for offline reviewing. (They said they could do something for us, but we'd have to pay for it.) Shai also very generously offered to help me out with everything, so we all owe him thanks. (But especially me.)

If you notice anything not working right with the site, please let me know right away.

Saturday, October 11, 2008

Protecting Privacy

Just a note that the National Academies Press has released its report (well, at 376 pages, it's really a book) Protecting Individual Privacy in the Struggle Against Terrorists: A Framework for Program Assessment, which is free to read online. You may have seen a news article on it somewhere or another. It's theory-relevant since Cynthia Dwork was on the committee that wrote it -- I'm guessing she played a very significant role in Appendix H: Data Mining and Information Fusion and/or Appendix L: The Science and Technology of Privacy Protection in particular. It's now on my to-read stack.

Wednesday, October 08, 2008


I went to a talk which was about a type of industrial software. At some point the speaker puts up a list about what typical corporate-research/programmer staff in this area do all day. The list was clearly meant to be a little humorous (inasmuch as people discussing such things can be). The last bullet was:
Find time to find a girlfriend.
Now, I'm not claiming to be most sensitive Neanderthal in the cave, but I am the father of three daughters, and this raised my hackles. The small number of women in the audience didn't seem to notice or mind, but maybe they did, or maybe one would the next time he gave the talk. As a field, this is exactly the type of throwaway comment that we have to, repeat, have to avoid.

I mentioned it to the speaker afterward, and to his credit, he was not defensive, and said he'd remove it or change "girlfriend" to the gender-neutral "significant other". (I'd vote for removal. Why even go with the stereotype computer scientists can't find love?)

Friday, October 03, 2008

Latest PhD Comics

I occasionally read PhD comics. This last one explains why our enrollments will be going up again; the one previous just made me laugh. (Excuse me now, I have to go sit back and enjoy as the rest of the world crumbles.)

Thursday, October 02, 2008

The Stupidest NSF Review I've Had, Ever

It's come out before on this blog that I have a love/hate relationship with the NSF. I love that they give out money for research -- especially for mine! However, I am not always the biggest fan of their structure, processes, priorities, etc. (And I surely acknowledge that some of this is not "their" fault -- as a government agency, they've got government rules to follow.)

Still, the last reviews for a grant we didn't get contained just the stupidest comment, I really have to share it, because it just frightens me. I'm used to reviews I don't agree with -- the typical excuse not to fund a theory grant being, "The proposal doesn't explain how it will solve the proposed problems," while if I already knew how to solve the proposed problem, I'd have written the paper already -- but again, this goes beyond that. If this was just an excuse to not fund the proposal -- because the NSF for some reason never says "We only have money for the top 10% this year, and I'm afraid there are some better proposals," but instead has to have a reason -- that's fine, but I hope it's not a real reason.

This was a CDI proposal (so apologies to my co-authors, who do not necessarily share my opinions). The primary theme was mechanism design, but we focused on network formation and ad auctions as examples. One reviewer wrote:
[ad placement] is a very active research area for corporate research labs at places such as Yahoo and Google. Given the vast resources that are being invested at these corporate labs (that have hired top economists and computer scientists) and that have direct access to logs documenting advertiser and user behavior, it is unclear how much of a contribution an academic team can make here.
One review might be forgivable. The panel summary listed the following as a weakness:
- There were also questions regarding how this will
compete with much larger-scale multidisciplinary
efforts (CS-economics) of similar kind in
industry (Google, Yahoo!, MS, etc.).
Let's ignore that the PIs all have relationships with industry, that ad auctions was just an example (of pretty wide interest right now), and that (I had thought) working on problems of interest to industry is, generally, a good thing.

With this kind of thinking, there's no way a couple of graduate students from Stanford (or, more academically, a future well-known Cornell professor) should have been working on a silly thing like "search engine algorithms", since Altavista was already out there leading the way. (That's my #1 big example, fill in your own.)

Is "industry will do it better than you could" really a good reason not to pursue (or fund) a research topic? How many research areas would that really preclude? I'd assume we should also stop funding research in operating systems, compilers, and even computer security based on that comment, but oddly, I don't see a rush to cancel programs in those areas. Seriously, anonymous reviewer, if you actually meant that, congratulations, you've truly scared me about the future of NSF-sponsored research.

As an addendum, some comments from Harvard colleagues:

1. Where does the reviewer think the people who are going to go work for Google/Yahoo/Microsoft will be coming from?
2. This was the kind of thinking that led Harvard (a CS powerhouse post-WW II) to decide to drop computer science decades ago. IBM was doing it, no need to have a department doing research in the area. It took a while to recover from that decision....
3. That kind of comment is common for chip/architecture research. "Isn't Intel doing that already? How can you possibly contribute?" [I have increased empathy for architecture people.]

Wednesday, October 01, 2008

Conference heads-ups

Following the trend, a reminder that the FOCS 2008 hotel/pre-registration deadline is October 3.

On the STOC 2009 side, some announcements:
1) Submission date is Nov 17, BUT abstracts will be due Nov 10 -- following the same sort of procedure used for SODA. Spread the word, more info on the Web site shortly.
2) Accept/reject decisions should be out February 6, in response to those who have asked me. (It seems like every other conference in the rough vicinity will have paper deadlines the following week!)
3) The day before the conference is shaping up to be an event, about which I'll hopefully have more news for shortly.
4) It's looking like EasyChair will be the submission/review system. The risks of self-hosting just seems too severe at this point...