Because it’s garnering a significant amount of nationwide attention, I figured I’d come out of my quasi-retirement of late from blogging (really, I’ve just been bouncing around the country/world and super busy trying to get life started in a new place or three) to talk about the State of Colorado’s announcement that its teen contraception program led to a 40% drop in the teen pregnancy rate. Put another way, the teen birth rate dropped from 37 live births per 1,000 people in 2009, to 22 live births per 1,000 in 2012. This is a drop from significantly above the national average to significantly below, which is a huge accomplishment.
With those numbers, the teen pregnancy rate did indeed drop by 40%, the question is whether all of that is attributable to the program. Importantly, the press release notes:
Fertility rates among low-income women aged 15–24 were compared with expected trends. Abortion rates and births among high-risk women were tracked, and the numbers of infants receiving services through the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) were examined.
However, a true comparison with expected trends would require subtracting out the expected drop in teen pregnancy rates by identifying a comparison group (this is called a difference-in-difference strategy or a randomized control trial if the program was rolled out randomly, which is probably was not).
The Denver Post article, probably in the interest of journalistic integrity, interviewed some people about the findings, but in my opinion, not anyone with the ability to really evaluate the claim. Teen pregnancy rates have been falling in the US, as have overall birth rates, and likely would have fallen in Colorado regardless of whether these individuals received the program or not. From 2011 to 2012, the US teen birth rate fell by 6% alone. The question is whether they fell by more than they otherwise would have if the program had not been put in place. Or would they have increased?
While it seems that the state did some analysis to net out this effect from their press release, the 40% figure probably overstates the true effect of the program. It could also understate the true effect. If teenage sexual activity was also increasing among those groups targeted by the program, the expected pregnancy rate would have been higher, resulting in a larger difference. In all likelihood, the program did likely reduce the teen pregnancy rate, but I don’t think we know exactly by how much.