By Ruben Obregon
For the past year, news stories and studies have credited improved contraceptive use for 86% of the decline in teen pregnancy between 1995 and 2002. So far, this figure has remained largely unchallenged - until now.
I don't believe this figure accurately describes why pregnancy rates declined. Of course, I could be wrong - I'm not a statistician after all - and so I'd like to see what others think of my analysis. Regardless of where you stand on abortion and or contraception, I'd be interested in reading your opinion...
Here is why I believe this study has serious problems: (a full analysis can be found below).
1. Essentially, the study focuses on abstinence among those who have ever had sexual intercourse, and not among all teens. Granted, the study does take into account abstinence among all teens aged 15-19 in building the pregnancy risk index, but this is not the same as calculating the pregnancy rate, which is a different statistic.
The authors found that the 86% reduction in the pregnancy risk index, which they defined as the "percentage of women who were sexually active multiplied by contraceptive risk index", is due to improved contraceptive use.
This is not a finding that contraceptives are responsible for 86% of the decrease in pregnancy rates. But nevertheless the authors go on to credit the majority of the decline in the teen pregnancy rate with improved contraceptive use. *
Yet, without calculating the contributions of increased abstinence among all teens, and not just among those with a sexual history, one cannot accurately claim that contraception is responsible for a majority of the decline in teen pregnancy, as the authors attempt to do in this study.
2. In my opinion, in order properly contrast abstinence among all teens and contraceptive use in relation to overall pregnancy rates, a more thorough methodology is needed.
For example, such a methodology would have to first calculate the percentage of decline in the pregnancy rate is attributable to an increase in the number of teens who have never had intercourse, and then calculate how much of the remaining percentage is due to improved contraceptive use and increased abstinence among the sexually experienced.
Yet, such a methodology poses a problem for Santelli et all and the Guttmacher Institute - it would demonstrate that abstinence has indeed made significant contributions to the decline in teen pregnancy.
Why did these Guttmacher researchers change their methodology? I can only speculate that since past Guttmacher studies - including those written by Santelli - have shown that increased abstinence has has a significant impact on teen pregnancy rates, a change was needed.
A change had to be made in order to better attack funding for abstinence until marriage programs. After all, increased abstinence is bad for business for both the Guttmacher Institute and Planned Parenthood.
The change in methodology, in my opinion, reflects the fact that these researchers cannot win nor frame the debate if their own studies continue to demonstrate the effectiveness of abstinence on teen pregnancy rates.
In my opinion, at best the 86% figure given by the authors reflects a change in contraceptive use among those with a sexual history, and does not reflect the impact of increased abstinence among all teens.
If you'd like to read my analysis, click on the link below to read it...
* The teen pregnancy rate is the number of pregnancies per
1,000 women aged 15-19
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