No question about it – defense rules the NFL; consequently, and of more interest to us, it also rules the point spread.  

In the last eight Super Bowls, teams playing for the Lombardi trophy were both ranked in the top ten NFL defenses, the only exceptions being Atlanta in 1998 and St. Louis in 2001 (they both lost and did not cover).

The point is clear - defenses are to be relied upon and wagered on with relative certainty.  Defenses perform more consistently than do offenses and are, in my opinion, afforded the greatest weight when handicapping pro football. 

The table below shows the defensive ranking, total points allowed, average points per game and points allowed per 100 yards gained (PP100).  The defensive ranking is calculated using the PP100 statistic, as I consider it a more accurate indicator of a defense.  Take note that the better defense won and covered every Super Bowl over the last eight years, with one exception - the 2004 new England Patriots.

This strategy went 6-1-1 in the last eight Super Bowls.  Using it during the 2000 season also made money.  During weeks 5 through 16, it produced 48 winners and 27 losers, for a winning percentage of 64% and net wins of over 19 units.  See the detailed results for 2000.