There's new and stronger evidence to support one of the most provocative and controversial social theories of recent decades, namely that abortions reduce crime, two economists contend in a new paper published by the National Bureau of Economic Research.

John J. Donohue III of Stanford University and Steven D. Levitt of the University of Chicago first formally proposed the link between abortion and crime in an article published two years ago in the Quarterly Journal of Economics. Now they've updated that study with fresher data and a more detailed analysis, in large part to answer the many critics of their earlier work.

These researchers theorize that legal abortion reduces crime by making it easier for women to end unwanted pregnancies. By their reckoning, more abortions mean fewer neglected or abused children who would be more likely to end up in trouble with the law.

Since the 1973 Roe v. Wade decision made abortions more widely available, the generation born around this time should contain disproportionately more "wanted" children than earlier generations -- children who would be less likely to commit crimes when they grew up.

Three pieces of evidence support their claims. First, crime dropped sharply during the 1990s -- precisely the period in which the generation of children first affected by Roe v. Wade reached its peak of criminal activity. Second, the five states that legalized abortion in 1970, three years before the landmark abortion ruling, were the first to experience the drop in crime. Third, states with high abortion rates in the early 1970s experienced the biggest decline in crime, even after controlling for other factors usually associated with changes in the crime rate, they wrote.

Overall, Donohue and Levitt found that a 10 percent increase in the abortion rate was associated with a 1 percent decline in the crime rate. They estimated about half of the overall decline in the crime rate between 1991 and 1997 was due to legalized abortion.

Well, they got hammered by a small army of researchers who questioned their data, methods and findings. Among their critics: the researcher John R. Lott Jr., currently at the American Enterprise Institute, who produced a study that argued abortion caused crime by weakening moral values. Theodore Joyce, an economist at the City University of New York also challenged their results. He carefully analyzed the same data but did not find a negative relationship between abortion and crime in the six-year period from 1985 to 1990, or the time the Roe v. Wade generation should have been entering their peak crime years.

So Levitt and Donohue went back to their number crunching. They collected more data and redid their analysis -- and found that abortion seemed to have an even bigger impact on crime than they first estimated.

Instead of reducing homicides by about 14 percent, the new data suggested an 18 percent drop associated with abortion. Violent crime and property crime also went down as the abortion rate went up, and by a bigger amount than they had earlier forecast, they reported in their new study.

CONFERENCES: An interesting lineup for the mid-April confabulation: "Arts & Minds: A Conference on Cultural Diplomacy Amid Global Tensions." Organized by D.C.'s Center for Arts and Culture, Arts International and the National Arts Journalism Program, the conference features CIA historian Michael Warner; Pulitzer Prize-winning novelist Richard Ford; former Carter State Department spokesman Hodding Carter; the American Enterprise Institute's Joshua Muravchik; screenwriter John Romano ("Hill Street Blues," " L.A. Law," "Party of Five"); and former ambassador to France Felix Rohatyn.

PEOPLE: The Council on Foreign Relations is bringing on outspoken former White House cybersecurity chief Richard Clarke to lead a new First Responders Task Force. Clarke spent 11 years in the White House, and ran the counterterrorism office under both President Bush and President Bill Clinton. Council head Leslie H. Gelb said Clarke "is known as a giant dragon slayer."

Meanwhile, retired Air Force Gen. Joseph W. Ralston, until recently supreme allied commander in Europe, has signed up with the Center for Strategic and International Studies as a distinguished senior adviser. He will concentrate primarily on transatlantic security issues.

The Center for Public Integrity has hired its first director of communications and outreach: Ann Pincus, a former director of research at the U.S. Information Agency and vice president of communications at WETA. CPI has also hired Teo Furtado as deputy managing editor. Most recently, Furtado was an editorial consultant to Time Magazine.

The Brookings Institution, currently home to several prominent Clinton administration types, has just scored a Bushie: Former deputy treasury secretary Kenneth W. Dam has signed up as a senior fellow. Dam's former boss at treasury, Paul H. O'Neill, was asked to leave, and Dam resigned the day after O'Neill's successor, John W. Snow, was sworn in. The former University of Chicago provost also returns to teaching at Chicago's law school.

After 22 years in Washington, defense expert Ivan Eland has switched coasts, departing the D.C.-based Cato Institute to join the Oakland, Calif.-based Independent Institute, where he will head up a new Center on Peace and Liberty. Eland said part of the draw was "living by the beach instead of (frozen) ground zero."

Turkish scholar Rengin Gun recently joined the Atlantic Council for a one-year run as a senior fellow. Her previous position: deputy chief of the Terrorism and Conflict Studies Desk at the Center for Eurasian Strategic Studies in Ankara.