What Explained the Crime Drop of the 1990s?

Levitz' new book, "Freakinomics," is about the crime drop of the 1990s. Levitz argues that mass incarceration and lenient justice system are to blame for this decrease in crime. But criminologists say these theories don't hold up under scrutiny. The author says there's a huge amount of conservative, iron, rammed bullshit presented as harsh truths.