Although the Redskins lead the NFL with 4.2 quarterback traps per game, we really don't know how good the Washington pass rush is.

That's because the Redskins have faced the NFC's weakest level of opposition as far as this statistic goes. Their opponents have been dropped 3.2 times per game and rank 27th in the NFL.

By comparison, the Raiders rank second in this key defensive statistic, dropping passers 4.1 times. But they have played the NFL's toughest schedule in terms of defensive stats. Raiders opponents have allowed only 2.6 sacks per game.

A computer analysis shows that the difference in sacks is one of the most important statistics in the game. The five top teams in sack difference are: San Francisco, plus 1.8 sacks per game; Miami, plus 1.7; Chicago, plus 1.7; Washington, plus 1.4, and Denver, plus 1.2. All are playoff bound.

The five weakest teams are going nowhere: Minnesota, minus 2.5 sacks per game; Buffalo, minus 2.2; Atlanta, minus 1.9; Colts, minus 1.3, and Houston, minus 1.3.

About 20 percent of a team's performance in a given statistical area can be attributed to the level of opposition. With the league-leading Redskins dumping the passer 4.2 times per game and playing the easiest schedule, we might use this 20 percent rule to estimate their true strength.

This week, the Redskins play the Cardinals, last year's league leader in defensive sacks. The Cardinals drop opposing quarterbacks 3.3 times per game, ranking 11th. But they have played a tougher schedule than the Redskins. The computer analysis shows that one sack differential is worth 3 1/2 points -- thus, the winner should be on the plus side of the sack column Sunday.

Computer projections: Redskins over Cardinals by 6; Dolphins over Cowboys by 10; Giants over Saints by 5. Wild card teams: Giants and Rams.