John Lott of the American Enterprise Institute wrote a letter to the Wall Street Journal regarding Freakonomics. Here is the letter, published today:

Not surprisingly, Steven Levitt and Stephen Dubner’s new book ignores their academic critics, but Steve Landsburg’s review disappointingly does so too (April 13, p. D14). Take just the book’s first claim: unwanted children are more likely to grow up to be criminals and that abortion can therefore reduce crime, a plausible idea that has been around since the beginning of the abortion debate.

Yet, despite Levitt and Dubner’s claims, legalization doesn’t explain 75 percent of the drop in murder rates during the 1990s, and if anything the reverse is true. Their data had a serious error. The Planned Parenthood affiliated organization that supplied them with the data incorrectly claimed that when abortion was legalized during the late 1960s and early 1970s states went from a complete ban to complete legalization, but abortions had been allowed before complete legalization when the life or health of the mother was endangered. The Centers for Disease Control data show that before Roe v. Wade many states that had allowed abortions only when the life or health of the mother was endangered actually had higher abortion rates than states where it was completely “legal.”

If Levitt and Dubner were correct, crime rates should have first started falling among younger people who were first born after legalization. Only as they aged would you start seeing crime fall among older criminals. But in fact the precise opposite is true. Murder rates during the 1990s first started falling for the oldest criminals and very last for the youngest.

Readers interested in more on the abortion-crime hypothesis may want to also read a recent paper by Ted Joyce.