Steve Sailer asks an excellent question

In response to my last blog post, Steve Sailer posed the following question in the comments:

The abortion rate among whites fell from 19 in 1991 to 11 in 1999, according to the Alan Guttmacher Institute of Planned Parenthood. Should we thus soon expect an upturn in crime rates among white 14-17 year olds?

This is a great question. And the answer — no, we likely shouldn’t expect an upturn in crime — may surprise you.

The theory that Donohue and I put forth regarding a link between legalized abortion and crime was based on the following logic:

1) Unwanted children are at higher risk for crime
2) Legalized abortion reduced the number of unwanted children

and therefore

3) Legalized abortion reduced crime.

It isn’t abortion per se that matters, it is the number of unwanted children.

Legalization mattered because after abortion became legal the cost (financial, social stigma, availability, etc.) of getting an abortion plunged. When abortions got cheaper, women on the margin for having an unwanted child elected not to.

But the factors at work in the 1990s that led to declining numbers of abortions were probably not principally tied to an increase in the cost of abortions. Rather, it appears that the 1990s were a time when factors such as AIDS were leading people to, for instance, use condoms or abstain from sex altogether. Not conceiving an unwanted baby is equally effective in reducing unwantedness as having an abortion.

It is a subtle point, one that is missed by most people thinking about the issue, but whether more abortions should be associated with less crime, or possibly with more crime, hinges critically on whether the change in the number of abortions is due to a change in the price of abortions (a movement along the demand curve) or a change in the number of unwanted conceptions (a shift to a different demand curve). Only for movements along the demand curve does theory predict a negative relationship between abortion and crime. When changes in the numbers are due to shifts in the demand curve for abortion, the relationship between abortion and crime is actually positive!

Here’s another way to think about it. The total number of unwanted births is equal to the number of unwanted conceptions times the fraction of women who don’t abort those unwanted pregnancies. Let’s assume that a woman who has conceived an unwanted pregnancy is equally likely to get an abortion in the 1990s or the 1970s, but that because of fear of AIDS, people use condoms and have fewer unwanted conceptions. With fewer unwanted conceptions, there will be both fewer abortions and fewer unwanted births. In that case, lower 1990s abortions are a harbinger of future crime reductions, not future crime increases.

The only argument one could make for declining abortions in the 1990s leading to rising crime rates down the road would be if you think that various abortion restrictions like the Hyde Amendment, protests outside Planned Parenthood, etc. substantially raised the costs of getting an abortion. That may be true, but my sense is that most people who studied it don’t think these factors had such a big impact.

Along with Lars Lefgren, my former student now at BYU, I was writing a paper that made this point formally. Somewhere along the way got sidetracked and never finished it. We probably should because I am certain that before long someone who doesn’t understand the point will follow exactly the line of argument Steve Sailer put forth, not find a negative relationship between abortion and crime for kids born in the 1990s, and erroneously state that it invalidates the arguments Donohue and I made about the 1970s.