Here's Ilan Goldenberg's chart of the Pentagon's changing story about civilian casualties in Iraq:
Hat tip to Brian Katulis at CAP who clued me on to this issue and Spencer Ackerman has already got a great post on this.
Basically there are more serious questions about the violence numbers that are being reported out of Iraq. The Pentagon is congressionally mandated to produce a quarterly progress report to Congress measuring stability in Iraq. Each of these reports has a graphic measuring sectarian violence. The last four reports were August, 29 2006 (pg 35), November 30, 2006 (pg 24), March 2, 2007 (pg 17) and June 7, 2007 (pg 17).
I graphed the levels of sectarian violence from these various reports and found some confusing trends. The abnormalities have been labeled A, B and C. (There is no difference between the November report and the March report and thus they overlap).
It'd be nice to not need to hyper-scrutinize every random bit of official government data this way, but the idea that the Bush administration has no credibility on Iraq isn't just a cliché -- based on his record, one has no choice but to inquire and to be very suspicious.