To blitz or not to blitz? That is the question

My 9-year-old son scored a touchdown against me in "Madden 11" recently when he called a screen pass against my blitz.

Mistakes happen in real football, too.

NFC West teams had their share of live-and-learn moments to go with their successes when sending extra pressure against opposing offenses last season. After reading Eric D. Williams' recent piece referencing Seattle's reluctance to send all-out blitzes, I went through related numbers from ESPN Stats & Information.

The charts show how each NFC West defense fared in various statistical categories based on how many players rushed the passer on given plays last season. The numbers are interesting, but they cannot account for changing situations. I hope to break down the information by down in the future.

For now, here's a look at the numbers, beginning with the St. Louis Rams. They had the best pass defense in the division by most measures.

For reference, I added charts showing how Super Bowl participants Green Bay and Pittsburgh fared.

2010 St. Louis Rams Defense

The San Francisco 49ers were less apt than other teams in the division to bring extra pressure. They sent five or more rushers on 27.1 percent of opponents' pass plays, defined by attempts plus sacks.

When the 49ers did send extra pressure, opposing quarterbacks completed a higher percentage of their passes with a superior touchdown-to-interception ratio even though the 49ers did register sacks twice as frequently. Their ranking in sacks per pass play, defined as sacks divided by sacks plus attempts, rose from 17th to eighth when sending extra pressure.

2010 San Francisco 49ers Defense

First-year Arizona Cardinals defensive coordinator Ray Horton has promised to blitz frequently, including on the team's first play of the season. Sounds like a good idea. The Cardinals' pass defense fared significantly better in key statistical categories when sending at least five rushers last season.

2010 Arizona Cardinals Defense

The Seattle Seahawks did fare better statistically when they sent more than four rushers, but the gains were not dramatic. Their interception rate fell precipitously. Their ranking in sacks per pass play jumped from 25th to seventh in the NFL when sending at least five rushers.

2010 Seattle Seahawks Defense

The Packers ranked third in the NFL in sacks per pass play when sending four or fewer rushers. Only the Oakland Raiders (9.3 percent) and San Diego Chargers (7.9 percent) ranked higher. The Chargers were at 7.87 percent, compared to 7.85 percent for Green Bay.

2010 Green Bay Packers Defense

The Steelers' defense led the NFL in sacks per pass play when sending more than four rushers.

2010 Pittsburgh Steelers Defense