James Joyner links this NYT piece with the snarky comment:

I await the study that investigates New Years resolutions.

I tend to agree with commenter “steve,” who writes:

Too bad there are some in this country who want to make so called virginity pledges part of serious public policy. When serious people call for new years resolutions in order to solve serious socail [sic] problems your point will stand.

But I think there’s an interesting question here: why aren’t many of the pledges kept? I suspect it has to do with peer pressure: students who don’t sincerely want to make virginity pledges are pressured into them by religious groups they are affiliated with, parents, or friends. And, in general, people don’t keep pledges when there’s no effective sanctioning mechanism to ensure fealty to them; unless you’re female and get knocked up, nobody’s going to know whether or not you actually kept a virginity pledge.

That said, one other part of the study, as reported in USA Today, seemed a bit puzzling:

The study also found that in communities where at least 20% of adolescents pledged the STD rates for everyone combined was 8.9%. In communities with less than 7% pledgers, the STD rate was 5.5%.

Not only is this a massive ecological inference problem (there’s absolutely no way to show causality here), the causal mechanism doesn’t even function right: adolescents are a relatively small part of the population, dwarfed by the sexually active adult population. Nor is there any test of whether the pledge rate affects STD rates over time—which at least might get at the question of whether pledges have some aggregate effect on STD incidence. Most odd.

Anyway, I tend to agree with critics that government-led efforts to encourage abstinence—a cornerstone of both the Bush and Clinton administrations’ “sex ed” policy*—are likely to be completely ineffective, if not counterproductive, in reducing teen pregnancy and STD transmission. The feds should find something better to waste our money on instead…