We know that it was a surprise to see the Cardinals play well in the playoffs after they crashed at the end of the regular season. But was this turnaround really as unprecedented as we made it out to be?
Oh, yes. Yes, it was.
From Week 13 through Week 16, Arizona had three games with a single-game DVOA rating below -60%. That's very, very bad. Only three other teams this year had three games that bad over a four-game period: Detroit, Kansas City, and St. Louis (twice). You may notice these are the three worst teams of 2008 according to both total DVOA and win-loss record.
Then, from Week 17 through Week 21 (the Super Bowl), Arizona had a single-game DVOA rating above 35% for five straight games. A streak this good is just as rare. Only one other team this season managed a DVOA rating above 30% in at least five straight games: the New York Giants, from Week 7 through Week 12.
Has there ever been a team that followed up a streak that bad with a streak that good? Certainly not during the DVOA Era, which goes back to 1995 -- even if we loosen up the requirements a little bit.
I went looking for teams that put up
1) at least three games with DVOA below -40% over a four-week span, and then
2) at least three games with DVOA above 40% over a four-week span.
Only one team since 1995 qualifies: the 2008 Arizona Cardinals.
Then, I changed the baseline to three games below -30% followed by three games above 30%.
Now two teams qualify: the 2008 Arizona Cardinals and the 2003 Minnesota Vikings. The Vikings had three horrible games below -50% between Week 10 and Week 13, then managed DVOA above 30% in Weeks 14, 16, and 17. Unfortunately, they blew their playoff spot when Nate Poole caught a game-winning touchdown in the final minute of that Week 17 game, and Arizona beat the Vikings 18-17.
What happens if we change the baseline to three games below -25% followed by three games above 25%?
Now four teams qualify. Along with the 2008 Cardinals and 2003 Vikings, we have:
1) The 2007 New York Giants, who had three games below -25% between Week 12 and Week 15 and then five straight games above 45% from Week 17 through Week 21, thus winning the Super Bowl, and
2) The 2003 St. Louis Rams, who were all over the map all season. The Rams had DVOA ratings below -25% in Weeks 9, 11, 12, and 17 but DVOA ratings above 25% in Weeks 6-8, 10, 13, 15, and 16.
The Cardinals' performance is far beyond this baseline, and yet there are still only three other teams since 1995 that had a similar run of good play after a run of awful play.
If we change the baseline to three games below -20% and then three games above 20%, we get a baseline matched by roughly two teams per season. The other team for 2008 was Dallas, which had three games with DVOA below -20% from Week 6 through Week 9 (the Brad Johnson games) followed by games with DVOA above 20% in Weeks 11-13.