Saturday, February 11, 2012

Lies, damned lies and the Guttmacher 98%

Figures often beguile me, particularly when I have the arranging of them myself; in which case the remark attributed to Disraeli would often apply with justice and force: "There are three kinds of lies: lies, damned lies and statistics."
Mark Twain's Own Autobiography: The Chapters  from the North American Review

I've written before that the same Guttmacher Institute report which claims that "98% of Catholic Women have used birth control" also notes that “Nearly 70 percent of Catholic women use sterilization, the birth control pill or an IUD".  Well, thanks to Lydia McGrew at What's Wrong with the World, we have some further exposition into the study itself rather than the (biased) Reuters report.

First, the study was limited to women between 15 and 44.  While it's somewhat reasonable, as 45-50 gets into the pre-menopausal range, it leaves out all the women who didn't use contraceptives prior to menopause. So the study is about current contraceptive use; the claim as constructed misleadingly attempts to extend that "98%" figure to cover women who are 45 and older.

Next, having left out all the ≥ 45 women who never used birth control, the study next trims out women who aren't sexually active (no sex in 3+ months).  Lydia quips, "There go all the nuns," but there also go all the women who, for one reason or another, have opted for celibacy and/or chastity, like my friends the Bright Maidens.


Next, the study subtracts pregnant women, post-partum women and women trying to get pregnant.  Now, it makes sense to subtract them if all you're doing is taking a snapshot of who's using contraception at this time frame.  But if you're trying to construct a general claim, then you need to look at a) whether these women used birth control beforehand, and b) whether they'll go back to birth control afterwards.  Also, as Lydia points out: 

Whether or not [the study] included women who considered themselves neither trying nor not trying to get pregnant (there are some such women in the world) is unclear. It's also unclear whether it included women who have had their reproductive organs removed because of some medical problem. Presumably the study was intended to exclude women in both of these categories, as neither would count as a woman "at risk of an unintended pregnancy."

Finally, Lydia includes in an update:

[The "98%" statistic] is including all the Catholic women who expressly told researchers that they used "no method" to avoid pregnancy. In the table, that is 11%. The 98% statistic is apparently derived by subtracting only the 2% who said that they used NFP from 100%. So women who said they used no method of contraception are apparently being included in a statistic about how many Catholic women use contraception. How's that for crazy?
It's not just crazy, it's actively dishonest.  If your purpose is to demonstrate how many Catholic women are actively using contraception, then you need to subtract the 11%, which would give you 87%.  By including the 11% in the number, the report undermines its own claim to be a "snapshot" and defeats the logic of the exclusionary choices (the 45+ women, the sexually inactive, the "are/were/trying to be pregnant" women).

You must remember — first, last and always — that the Guttmacher Institute is the social-science sock puppet of the National Abortion Rights Action League.  While they're occasionally capable of respectable science, their mandate and raison d'être is to make abortion and contraception look good.  If they can spin the data in their favor, spin they will.  They know that relatively few people look beyond the top-line numbers or dig further into reports, so their news releases will bury unfavorable conclusions and trumpet the culture of death's idea of "good news".  The Guttmacher Institute can't be trusted to tell the unvarnished truth, even when the truth appears to favor them.

Always look beyond the top-line numbers!

Thanks again to Lydia McGrew and her friend Neil Manson, whose nose for numbers with high FQ (Fishiness Quotient) led her to question the meme!