Have 98 percent of Catholic women used contraceptives? Not quite. - The Washington Post

Link: http://www.washingtonpost.com/blogs/ezra-klein/post/have-98-percent-of-catholic-women-used-contraceptives-not-quite/2012/02/14/gIQAZszTDR_blog.html (via shareaholic.com)

98% of statistics say something other than what's in the headlines.

Lydia McGrew questions whether 98 percent of Catholic women have actually used contraceptives, a figure that became ubiquitous in last week's birth control debate. She parses the research behind the stat, which comes from a 2011 Guttmacher Institute study:

The survey was limited to women between 15-44. Ah, well, that explains how we weren't including the elderly, but it also means that the silly "percent of all Catholic women" thing should be chucked out right from the beginning. More strikingly...it excluded any women who were a) not sexually active, where that is defined as having had sexual intercourse in the past three months (there go all the nuns), b) postpartum, c) pregnant, or d) trying to get pregnant! In other words, the study was specifically designed to include only women for whom a pregnancy would be unintended and who are "at risk" of becoming pregnant...a statistic based on a study that explicitly excluded those who have no use for contraception is obviously irrelevant to a question about the percentage of Catholic women who have a use for contraception.

....
Jones's study does not find that 98 percent of all Catholic women have used contraceptives. What it does, however, bear out is the claim that many have made with this statistic: that sexually-active, Catholic women do tend to use contraceptives at the same rate as their non-Catholic counterparts. On that front, Jones looked at women who had been sexually active within the past three months. You can see the results of that question in the chart above, where contraceptive use of Catholics look virtually identical to those of all women.

At Lydia McGrew's post, linked above, she concludes with:

The statistics in the Guttmacher study appear to be okay for the purpose for which the study was originally intended. The intention of the study was to answer something like the following question: "Among women of various religious groups who are now sexually active but do not wish to become pregnant, what percentage use different methods of avoiding pregnancy?" But the purpose for which the statistic for Catholic women from the study is now being used is to argue, "A very high percentage of Catholic women (or, perhaps, Catholic women of child-bearing age) are currently not following the Catholic Church's teachings on sex and contraception and have a use for contraception forbidden by the Catholic Church."
For that purpose, these statistics are bogus.