Posted by ESPN.com's Kevin Seifert
Continuing our series of year-end statistical analysis, we bring you the red-flag rates of the NFC North's four coaches in 2008.
Yes, ESPN Stats & Information tracks every challenge in regular-season games and sorts them by rate of reversal. By that standard, the most successful black and blue challenger was Green Bay coach Mike McCarthy, who managed to get 57 percent of his challenges reversed.
Meanwhile, Minnesota coach Brad Childress tied for third among NFL coaches with 11 total challenges. He got five reversed.
The full list, attributed to teams and ranked by reversal rate: