Last week at Five Thirty Eight, Nate Silver noted that San Antonio Spurs head coach Gregg Popovich has produced an excellent record against the spread. He also checked in football’s version of Pop, Bill Belichick, and came to the same conclusion: Belichick hasn’t just been great, but he’s been great against the spread, too.

My database on point spreads goes back to 1978, so I went ahead and calculated the Against-The-Spread record of each head coach over the last 36 seasons. According to my numbers, Belichick has “covered” or won 40 more games against the spread than he’s lost, the most over this period. The table below shows the 122 men who have coached at least 50 games or who were active in 2013.

Here’s how to read Belichick’s line: He has been coaching since 1991 (coaches who began before 1978 are included, but only their post-1977 seasons are counted (and only if they coached 50+ games since 1978)) and was last coaching in 2013. Over that time, he has coached in 332 games, including the post-season. His record against the spread is 182-142-8, which gives him a 0.562 winning percentage (ignoring ties). His real record is 218-114-0, which gives him a 0.657 winning percentage (again, including the playoffs). The table is sorted by the last category, which represents the difference beteween his number of wins against the spread and his number of losses against the spread.

As always, the table is fully sortable and searchable. For example, if you double click the “ATS Win%” column and then double click the “Last Yr” column, the table will sort by ATS winning percentages for men who were active in 2013. Using that methodology, Arizona head coach Bruce Arians jumps to the top of the list, courtesy of a an excellent 17-7-4 record against the spread (which includes his time as the interim head coach of the Colts in 2012). That’s an amazing run for Arians, and I’ve been a fan of his work, boneheaded decisions aside.

So is Belichick the greatest head coach against the spread? It’s always challenging comparing records of teams or coaches with wildly disparate numbers of games. For example, Belichick’s 0.562 winning percentage is incredible over 332 games, but how does that compare to Jim Harbaugh having a 63% rate over 56 games? Frankly, there’s no perfect answer.

Neil has written that you can add a certain number of wins and losses to a team’s record to get their true winning percentage. What’s nice about this feature is that it is that you can use it at any point in the season; the dummy games just make up a smaller percentage of the formula as more real games are included.

So, for example, to make Belichick and Harbaugh have the same ATS winning percentage, you would need to add 46 wins and 46 losses to each of their records. That would give Harbaugh 80 covers and 66 losses (0.548) and Belichick 228 covers and 188 losses (0.548). Of course, I don’t actually know what the “right” number of games of .500-level play one would need to include, but I think the break-even point of 92 games helps to frame the discussion.

For say, Arians compared to Belichick, you need to add 38 wins and 38 losses. For Bill Walsh, it’s 136 wins and 136 losses. Reasonable people can disagree, but I’d probably lean towards arguing that Walsh’s ATS record is more impressive than Belichick’s, while it’s hard to get a sense on how to compare Belichick and Harbaugh.

Dearly beloved Bum Phillips winds up in last place on this list using the “wins minus losses” formula, although Mike Martz could give him a run depending on how you adjust for games played. The Ryan father/son combo both check in as above-average against-the-spread, with Buddy Ryan being one of 14 men on the list to have a winning record against-the-spread and a losing record in general. His son, Rex Ryan, has managed to be slightly above average in both ATS record and general record, although he’s been slightly above average in the least boring way imaginable. As for our old friend, Marty Schottenheimer? His career is viewed very favorably under this formula, and he is the only coach in the top 8 not to win a Super Bowl.

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