A lot of readers have suggested that I am not a helpful blogger because I refer people to other studies for data to support my arguments. These critics are probably right. Were I devoted to blogging full time, I would quote all the data and summarize all of the studies, thereby getting nothing else done. I had assumed when I started my blog messages that people would pause, think, and look up facts. A few have, but most seem to have opinions they like to express quickly. There is nothing wrong with this, except that it doesn't advance knowledge. Let me join the opinion parade by offering a few of my own: This country imprisons too many people on drug charges with little observable effect. A better solution can be found in Hawaii, where a judge uses his powers to keep drug users in treatment programs (it's called Project Hope; look it up). The costs of crime are hard to measure (so are the costs of confinement). The reader who does not want to drive five miles to find the book, Prison State, that discusses this in detail is wasting my time and his. It is not hard to study deterring crime, but I can't imagine trying to teach someone in a blog how to do a regression analysis. I wish I could do that, but it would take time, and blog commenters seem not to have much time.

Now for a few more facts, but I warn you that to believe my assertions you will actually have to go out and read something. Intensive Probation: This is a good idea, but so far the studies of it have not suggested it lowers the crime rate. I wish it did, because it is cheaper than prison. The chief study, done at RAND, compared probationers under intensive supervision with similar ones not under such control. There as no difference in their crime rates while under supervision. There are two possible explanations for this: Either there was no difference in crime rates, or those under intensive supervision had more crimes noticed by their probation officers.

The effect of prison on crime rates: The chief study is by William Spelman and appears in the book, The Crime Drop in America, edited by Alfred Blumstein and Joel Wallman (2000).

The problem of the mentally ill in prison: This is a very large problem, caused in part by the dramatic drop in the number of mentally ill people in mental institutions. De-institutionalizing the mentally ill may have been a good idea, but the price we pay for it is to have a big increased of the mentally ill in prison. I would prefer that they be in mental health care institutions, but our society does not let that happen.

Abortion and crime rates: Steven Levitt is one of the authors of the study claiming, on the basis of a study of crime rates in five states where abortion was legal before Roe v. Wade and the 47 states where it became legal after Roe v. Wade, that abortion reduced the number of "unwanted children" and hence helped lower the crime rate. Levitt may be right, but to show that it is first necessary to count abortions in many states where, though it was illegal before Roe, occurred anyway to protect the health of the mother, and to control for other factors that affect the crime besides the number of "unwanted" children.