> There are reasons to be skeptical of any claim based on correlations between such widely separated variables as lead exposure (the cause) and crime (the effect). Consuming lead does not instantly turn someone i nto a criminal in the way that consuming vitamin C cures scurvy. It affects the child’s developing brain, which makes the child duller and more impulsive, which, in some children, and under the right circumstances, leads them to grow up to make short - sight ed and risky choices, which, in some children and under the right circumstances, leads them to commit crimes, which, if enough young people act in the same way and at the same time, affects the crime rate. The lead hypothesis correlates the first and last link in this chain, but it would be more convincing if there were evidence about the intervening links.

source - http://stevenpinker.com/files/pinker/files/pinker_comments_o...

Or the non-effect of them.

Crime rates have dropped drastically across the board, across the country, in many places that didn't make their policing policies more fascist as NYC's government chose to.

From the MJ article:

  Second, and far more puzzling, it's not just New York that has
  seen a big drop in crime. In city after city, violent crime peaked
  in the early '90s and then began a steady and spectacular
  decline. Washington, DC, didn't have either Giuliani or Bratton, but
  its violent crime rate has dropped 58 percent since its
  peak. Dallas' has fallen 70 percent. Newark: 74 percent. Los
  Angeles: 78 percent.

  There must be more going on here than just a change in policing
  tactics in one city.