Sunday, February 21, 2010

NFL: How points were scored in the 2009 regular season

I went through PFR's list of box score data for every regular season game played in the 2009 season, and compiled the following tallies:

OffensePassing TD 711 4266
Rushing TD 428 2568
2-point conversion 24 486882
DefensePick-6 48 288
Fumble-6 26 156
Safety 14 28472
SpecialField goals 756 2268
Teams Extra points 1163 1163
Kickoff return 18 108
Punt return 10 60
Blocked punt return4 24
Blocked FG return 2 123635
Total 10989


  • PFR's data seems to be mostly OK, although there are some obvious errors. This game, for example, has a touchdown being scored on a "-21 yard fumble return".

  • All passing and rushing touchdowns are credited to the offense, even though there was at least one scored by special teams. There's no reliable way to tell when a touchdown is scored on special teams using PFR's score format.

  • Another deficiency of PFR's score format: when a conversion attempt fails after a touchdown, it doesn't indicate whether it was an extra point try (and whether it was a bad snap, a bad kick, or a block), or whether it was a 2-point try.

    There were 60 failed conversions. According to this article [], there were 53 2-point conversion tries this season, which means that 29 failed 2-point conversions and 31 failed extra points.

    That gives a 97.6% success rate for extra points, and a 45.3% success rate for 2-point conversions. That may not seem like much, but getting 2 points on success doubles the effectiveness (for an extra point, expected value is .976, for a 2-point conversion, expected value is .906). Of course, that's over the course of a season for 32 teams. Which doesn't always help in one game, one team, one play, for a single good-or-bad outcome.

  • I've said before I'm generally not a big fan of 2-point conversions; I was actually rather surprised by how infrequently they were attempted (53 tries/1163 TDs = 4.6% of the time).

  • I was also surprised by how low the defensive scoring was compared to offense and special teams. As important as a defensive score can be to the course of a game, in terms of total points scored, it's pretty minor.

  • More scoring data coming as soon as I get the box score information parsed out to a more convenient format.