Assorted links

1. New Freakonomics study guide, explained and downloadable here.  Elsewhere on the Steve Levitt front, he argues with Roland Fryer that black and white kids have roughly the same mental abilities when measured at age one.

2. Google map of Mars, hat tip to Yana.

3. Here is a new cost-benefit study of the war in Iraq, from a hawk-friendly point of view.  The authors are Steve Davis, Kevin Murphy, and Bob Topel; I’ll let you know more once I’ve read it.