What is "Strength of Victory"?

Question

The NFL lists the following Tiebreaking Procedures to break ties within a division:

1. Head-to-head (best won-lost-tied percentage in games between the clubs).
2. Best won-lost-tied percentage in games played within the division.
3. Best won-lost-tied percentage in common games.
4. Best won-lost-tied percentage in games played within the conference.
5. Strength of victory.
6. Strength of schedule.
7. Best combined ranking among conference teams in points scored and points allowed.
8. Best combined ranking among all teams in points scored and points allowed.
9. Best net points in common games.
10. Best net points in all games.
11. Best net touchdowns in all games.
12. Coin toss

How is "strength of victory" determined?

Answer 1

According to this article from Boston.com, strength of victory is the composite record of the teams that the team in question has defeated:

Using strength of schedule (the composite record of all opponents) and strength of victory (the composite record of teams defeated), New England was in the middle of the pack among the 12 teams that made the playoffs in the NFL.

About.com has a similar definition:

Definition: A part of the NFL's tiebreaking proceedure, strength of victory is figured by calculating the combined winning percentage of the opponents a team has beaten.

Examples: If two teams end with identical records, combine the records of the opponents in each of the team's wins and calculate the total winning percentage. The team whose opponents have the higher winning percentage wins the tiebreaker.

For example, if team A has two victories (one with a 8-8 record and another with a 0-16 record), its strength of victory is 0.250. If team B has also two wins (over opponents that are 8-8 and 12-4), then its strength of victory is 0.625.