AccuScore simulation: AFC championship game

AccuScore simulation: AFC championship game
By Stephen Oh, AccuScore Analyst,
January 14, 2008 has run more than 10,000 simulations for Yahoo! Sports, calculating how each team's performance changes in response to game conditions, opponent's abilities, roster moves, weather and more. Each game is simulated one play at a time and the game is replayed a minimum of 10,000 times to generate forecasted winning percentages, player statistics and a variety of game-changing scenarios. Here's's analysis of the AFC championship game.


The Chargers pulled off the big road upset against the Colts, but things do not look good for the Chargers in New England. Even if LaDainian Tomlinson, Philip Rivers and Antonio Gates were not hurt, the Patriots would be heavy favorites at home. The Patriots are winning nearly 90 percent of simulations, converting over 53 percent of third downs. Tom Brady completes 70 percent of his passes for 333 yards and over 3 TD passes per simulation.

Laurence Maroney is actually out-rushing LT on both a per carry and total rushing yards basis (Maroney 4.3 ypc vs. LT 4.1). For San Diego to pull off the huge upset, it needs Rivers to pass for at least 2 TDs and no interceptions. In simulation losses, Rivers averages 1 TD pass and 1.1 INTs, but in simulation wins he has a 3-1 touchdown-to-interception ratio.

The Chargers' defense needs to intercept Brady twice. While San Diego managed to do that vs. Peyton Manning, the chances of Brady throwing 2 picks is under 10 percent. Look for Randy Moss to bounce back from his one-reception performance vs. the Jaguars with a huge 95 yards and at least 1 TD.

What if LT or Rivers or both are out?

It is blasphemous to say this, but Tomlinson's presence or absence does not have a huge impact on the outcome. Michael Turner and Darren Sproles both produced big plays vs. the Colts and Turner has been considered one of the best backup RBs in the league, if not the best. In simulations where LT is out, the Chargers won 9.5 percent of the time. With LT playing, they win 10.6 percent of the time. The team is better with LT playing, but not radically better.

San Diego Rushing Win% Rush YD YPC TD
W/ LT Playing 10.6% 25 98 3.9 0.55
W/ LT Playing 9.5% 23 93 4.0 0.51

Likewise, Rivers' presence/absence is not having a huge impact. Billy Volek has not played much since joining the Chargers, but his career completion percentage and touchdown rate are virtually the same as Rivers'. However, Volek does throw 15 percent more interceptions. If Rivers is out, the Chargers win 9.8 percent of simulations vs 10.6 percent with Rivers. Again, the Chargers are better with Rivers, but not radically better.

San Diego Win% CMP ATT % YD TD INT
Philip Rivers 10.6% 19.8 32.8 60.4% 214 1.3 1.2
Billy Volek 9.8% 19.1 32.1 59.5% 206 1.3 1.3

If both LT and Rivers are out, the Chargers win just 8.1 percent of simulations. While this represents a 2.5 percentage point drop, that does translate into 23 percent fewer wins.

Scenarios NE SD
BASELINE 89.4% 10.6%
No Rivers or LT 91.9% 8.1%

What If San Diego had home-field advantage?

The Patriots upset the Chargers in San Diego last year and this year would be no different. Early weather forecasts have the high to be around 20 degrees, but without precipitation. If the game were in San Diego, the Chargers' chances go from 10.6% all the way to 28.8%. So the Chargers' chances nearly triple, but they would still be a full 7-point underdog at home to the 17-0 Patriots.

Scenarios NE SD Score
San Diego at New England 89.4% 10.6% 32-17
New England at San Diego 71.2% 28.8% 28-21

Antonio Cromartie makes a big difference

The Chargers were beaten badly in Week 2 by the Patriots. New England came out firing through the air, passing 15 of their first 18 plays. Antonio Cromartie did not play that week, but came off the bench to become a Pro Bowler with 10 interceptions. He had a key interception to end the first half in Indianapolis. Cromartie deserved to make the Pro Bowl, not only because of the number of interceptions he had, but also his presence led to a lower completion percentage and fewer long pass completions by opposing QBs. In simulations where Cromartie does not play, the Chargers win just 7.4 percent. In this specific matchup, Cromartie is having a larger impact on the outcome than offensive stars, LT and Rivers.

Tom Brady NE Win% CMP ATT % YD TD INT
Baseline 89.4% 24.0 35.3 68.0% 327 3.1 1.0
W/ Cromartie Not Playing 92.6% 24.9 34.9 71.3% 346 3.5 0.8

Wes Welker's impact

Wes Welker may have dropped one notable pass vs the Jags, but his presence obviously was a huge part of the Patriots' record-breaking season. In simulations where Welker did not play, the Patriots only won 84 percent of the time, nearly 5.5 percentage points lower in winning percentage. Brady's forecasted passing yards are 327 yards with Welker but just 298 without him and his touchdowns are down 0.8 per simulation. The big difference you see is in third-down conversion percentage which goes down over 5 percentage points without Welker.

Tom Brady NE Win% 3rd Down CMP ATT % YD TD INT
Baseline 89.4% 53.4% 24.0 35.3 68.0% 327 3.1 1.0
W/ Wes Welker Out 84.1% 48.2% 21.9 33.5 65.4% 298 2.3 1.0

For more information on AccuScore’s NFL Predictions, visit

Updated on Monday, Jan 14, 2008 11:47 pm, EST

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