Here’s a useful table to contemplate now that we’re in NFL playoff season:
Apparently the two West divisions were the worst, and second-worst performances since the AFL-NFL merger. He then offers us some questionable statistical analysis under the guise of elucidated “conspicuous trends” from the history of this data:
The most compelling of these is that 26 of the 37 Super Bowl winners since the merger came from divisions that placed in the top three in win percentage during that season. This trend gets even stronger if the start year is moved to 1977, as 25 of the 30 world champions in that time hailed from one of the top three divisions based on win percentage. This trend stretched beyond Super Bowl champs, as 42 of the 72 conference champions since the merger came from the top three divisions. (These numbers don’t include the 1982 season because divisional play was not used that year.)
The historical evidence also shows strong indications for playoff teams that come from the bottom divisions. There were six divisions from 1970 through 2001, and only one time during that era did a team that came from the division with the worst win percentage win a Super Bowl (1999 St. Louis Rams). In fact, playoff teams from the sixth division during those years won only 24 playoff games, and seven of those were wild-card victories.
Another way of looking at this is that good teams tend to win the Super Bowl, good teams tend to have very good regular season records, and since NFL divisions are small having a very good team in your division tends to pull your division’s overall record upward.