Tuesday, May 22, 2007

Abortion Statistics

Vox Nova does it again. Today they have a very intriguing post on abortions statistics, with the goal of finding out how best to reduce the number of abortions in the United States. Here are highlights:

What does abortion in the United States look like? The Guttmacher Institute explores this issue in some detail. For a start, it notes that 57% of women opting for abortion are economically disadvantaged. In fact, the abortion rate among women living below the federal poverty level ($9,570 for a single woman with no children) is more than four times that of women above 300% of the poverty level (44 vs. 10 abortions per 1,000 women). And when asked to give reasons for abortion, three-quarters of women say that cannot afford a child. At the same time, black women are almost four times as likely as white women to have an abortion, and Hispanic women are two and a half life times as likely. Almost half of women terminating their pregnancies have had previous abortions, and 60 percent of abortions are concentrated among women who already have children.

Clearly, the importance of economic factors is stunningly obvious. Let's explore some of the larger trends. The Guttmacher Institute also presents detailed statistics on the abortion rate (abortions per 1000 women, age 15-44) and the abortion ratio (abortions per 100 pregnancies ending in abortion or live birth). Since 1980, the pattern of abortion has been trending downwards. The rate fell by almost 10 percentage points since 1980. Although the trend was more or less continuous, the steepest decline occurred during the 1990s. Matching rates of decline to presidential terms is enlightening. During Reagan's eight years, and the first Bush's term, the average abortion rate fell by 0.3 percentage points a year. But under Clinton, this rose to an annual average 0.5 percentage points. Under the second Bush (with the caveat that data only go to 2003), the rate of decline fell by 0.1 percentage points a year, practical standstill. The data for the abortion ratio are even more stark: here, the decline under Clinton is double that of the overall Republican average. So, there we have a seeming paradox: the largest decline in abortion took place under the sole Democratic presidential regime over this period. And yet the pro-life movement is strangely silent, and still hitches its wagon to the fortunes of the Republican party.

Let's go a little further with this empirical exercise and look at poverty rates. The poverty rate, whether measured by individuals or families rose under the first Bush administration (average half percentage point a year), fell dramatically under Clinton (average half percentage point a year), and rose again under the younger Bush (quarter percentage point a year). Are these trends related? Casual observation would say yes. But let's get a little more rigorous, and look at some empirical evidence. In particular, let's do a simple ordinary least squares regression of the abortion rate and the abortion ratio on a constant plus the poverty rate, 1980-2003. Here are the results:

Abortion rate = 2.06 + 1.71 * Poverty rate (R-squared= 0.37)

Abortion ratio = 9.43 + 1.32 * Poverty rate (R-squared= 0.44).

Both poverty coefficients are (highly) significant at the 1 percent level. This suggests that if we can reduce the poverty rate, there will be a more-than-proportionate reduction in abortion. Of course, these results can be challenged on the grounds that the data could be non-stationary. Running the regression in first differences should remove trends:

Change in abortion ratio = -0.25 + 0.37 * Change in poverty rate

Again, this is significant at the 1 percent level (but using the abortion rate is not). Remember, this is a very simple methodology to explore a rather basic hypothesis. But it seems clear that economic factors, insofar as they affect poverty, affect abortion patterns. Mapping these results into policy would suggest that the pro-life movement should broaden its scope to encompass economic as well as coercive strategies, since the ultimate goal is the reduction in abortions. It is also for this reason that I am highly skeptical about the need to vote Republican on pro-life grounds. But can the pro-life movement wrest itself from the grasp of the Republican party?

Read it all.

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