THE Obama administration's decision to compel Catholic universities, hospitals and charities to pay for insurance that covers contraception provides a good opportunity to riff off of my colleague's post on opinions that are beyond the reach of data. The administration is now walking back this decision, but let's deal with the original policy. It would seem that many Americans hold an immutable belief that the policy was wrong. And they hold this view in the face of data which show that women, men and society in general are better off when contraception is easily accessible. 

Nearly all sexually-active women (which is to say the majority of women) use contraception. Even among Catholics and Evangelicals, contraception use is the norm. Many would consider this reason enough to compel employers to provide coverage. But there are also reasons that may appeal more to a churchgoing conscience. As Adam Sonfield at the Guttmacher Insitute points out, there is a large body of evidence that shows contraception use has helped women avoid unintended pregnancies, which in turn has led to lower abotion rates, healthier babies, stronger marriages and improved social and economic conditions for women.

For example, Charles Westoff of Princeton University found that as Central Asian and eastern European countries embraced the use of modern contraception their abortion rates substantially declined. Closer to home, a study by a group of doctors published in the American Journal of Public Health found that the decline in pregnancy rates amongst American teens "appears to be following the patterns observed in other developed countries, where improved contraceptive use has been the primary determinant of declining rates." (Teen pregnancy is now at a 30-year low, thanks in large part to increased contraception use. Studies have also shown that greater availability of contraception doesn't lead to an increase in sexual activity.) Another study in California found that the state's family-planning programme, which provided contraception to nearly 1m women in 2007, averted about 300,000 unintended pregnancies, over 100,000 abortions, and 38,000 miscarriages.

Other studies show that proper birth spacing, for which contraception is an effective tool, leads to better perinatal outcomes. You probably don't need a study to tell you that unintended pregnancies put a strain on parental relationships, but there is one. Apart from contraception's value in family planning, it also offers direct benefits for women's health. Studies have shown that hormonal methods of contraception are useful in the treatment of menstrual disorders, while oral contraceptives reduce a woman's risk of developing certain forms of cancer. This side of the issue recently came to the fore when the New York Times reported on a Georgetown law student who was denied coverage of the birth control prescribed to treat her polycystic ovary syndrome (she eventually had to have an ovary removed). 

All of this research, and much, much more, is out there (much of it can be found in the footnotes of the testimony provided by the Guttmacher Institute to Congress). Most all of it points to the benefits of making contraception easily accessible. But I don't think any of it will change the mind of someone like Rick Santorum, who believes contraception is "a license to do things in a sexual realm that is counter to how things are supposed to be." And this is probably what Charles Murray was talking about when he wrote that "many of our opinions about policy are grounded on premises about the nature of human life and human society that are beyond the reach of data." They are grounded on premises about how things are supposed to be, as Mr Santorum says, and that's not up for debate. I'll leave you to debate whether that's a good thing.