Division among the wild-cards?

Despite having worse records than their opponents, both the San Diego Chargers and Arizona Cardinals won wild-card games last weekend. The Miami Dolphins and Minnesota Vikings each lost wild-card games despite having equal or better records than their opponents.

The common thread? All four teams did have home-field advantage. But according to historical numbers, that doesn't make a significant difference -- their status as a division winner does.

Division winners are 34-18 in wild-card games while home teams in wild-card games that have not involved division winners are only 23-15.

The second figure also carries an interesting caveat because home teams went 11-5 from 1978 to 1989** but only 12-10 from 1990 to 2001. The distinction is odd because in both cases, the wild-card games were held between the fourth and fifth seeds in the conference, although the introduction of free agency in 1993 could be one possible explanation for the sudden parity.

A brief historical review will help unpack the success of division winners in the wild-card round. The wild-card was introduced in 1978, but all three division winners received a bye week during wild-card weekend until 1990, when the postseason field was expanded from 10 to 12 teams.

From 1990 to 2001, four wild-card games were played but only two involved a division winner, because the conferences were aligned into three divisions. Division winners went 19-7 during those 13 seasons. In 2002, the NFL realigned both conferences into four divisions, resulting in two division winners playing in wild-card games. In the seven years since realignment, division winners are 17-11.

Perhaps, however, it's not surprising to see division winners fare well in the wild-card round. Quite simply, their regular season record is typically better than their opponent's.

When division winners have faced a wild-card team with a better regular season record, they are 4-3. When both teams have the same record, division winners are 7-3, and when division winners face a wild-card team with a worse record, they are 23-12.

**I did not include the 1982 strike season because an unusual playoff structure was utilized.