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How to lie with statistics
Jan. 7th, 2011 11:12 amJust so you all know: Vital Statistics when dealing with abortion: 2 statistics are often reported in ways that can be easily translated into percentages. One is the number of abortions performed divided by the number of women who are resident in the area-- fairly low: in 2006, 16.1 per 1000 women, i.e. 1.6% percent of the female population of the US between 15-44 had an abortion. That makes a useless statistic for politics, of course.
However, the most common statistics, the abortion ratio is
"number of abortions per 1,000 live births" -- that is, the number of abortions divided by the number of live births, times 1000.
What's wrong with this picture? It's usually reported in the news as "X percent of pregnancies" and the number seems to be the RATIO divided by 1000. Do the math.
Yup. By definition, the total number of *pregnancies* is going to be significantly larger than the number of live births-- it has to include live births, abortions, AND miscarriage. So, for instance, the 2009 abortion ratio for NYC would be 44%, as reported on the news, but when you correctly calculate what percentage of pregnancies in NYC end in abortions, it's 38%. (BTW, the number of miscarriages in NYC is also twice that of any other part of the state...)
In 2006, the CDC numbered 846,181 abortions in the US. I can't find a statistic for total pregnancies from the CDC, only teen pregnancies (and remember, the rate of teen pregnancies has *not* been 'skyrocketing' in recent years: CDC says "The US teen birth rate fell by more than one-third from 1991 through 2005, but then increased by 5 percent over two consecutive years. Data for 2008 and 2009, however, indicate that the long-term downward trend has resumed.")
However, the most common statistics, the abortion ratio is
"number of abortions per 1,000 live births" -- that is, the number of abortions divided by the number of live births, times 1000.
What's wrong with this picture? It's usually reported in the news as "X percent of pregnancies" and the number seems to be the RATIO divided by 1000. Do the math.
Yup. By definition, the total number of *pregnancies* is going to be significantly larger than the number of live births-- it has to include live births, abortions, AND miscarriage. So, for instance, the 2009 abortion ratio for NYC would be 44%, as reported on the news, but when you correctly calculate what percentage of pregnancies in NYC end in abortions, it's 38%. (BTW, the number of miscarriages in NYC is also twice that of any other part of the state...)
In 2006, the CDC numbered 846,181 abortions in the US. I can't find a statistic for total pregnancies from the CDC, only teen pregnancies (and remember, the rate of teen pregnancies has *not* been 'skyrocketing' in recent years: CDC says "The US teen birth rate fell by more than one-third from 1991 through 2005, but then increased by 5 percent over two consecutive years. Data for 2008 and 2009, however, indicate that the long-term downward trend has resumed.")
