Houston Texans' Advanced Stat of the Week: Win Probability

Nate DunlevyGuest ColumnistFebruary 19, 2013

The Lions couldn't contain Johnson.
The Lions couldn't contain Johnson.Mike Carter-USA TODAY Sports

No one will soon forget the Houston Texans' controversial but entertaining victory over the Detroit Lions on Thanksgiving Day.

Aside from giving us one of the all-time memorable challenges in NFL history, it also provides a great tutorial in this week's advanced stat: Win Probability.

Win Probability and its player-driven cousin Win Probability Added (WPA) are stats advanced by Brian Burke of Advanced NFL Stats. Win Probability calculates the likelihood that a team will win the game before each and every play. WPA adds up the impact that an individual player has on those odds.

For instance, a team with a 40-point lead with 45 seconds to play has a Win Probability of 100 percent. Win Probability is a stat that explains what happened after the fact. Swings in Win Probability illustrate which plays had the most impact on a game.

These plays can be charted to produce a graphical representation of the swings of NFL games. For games with twists and turns, these charts can be dynamic.

The graph of the Detroit-Houston game is a statistical representation of the roller-coaster ride fans' stomachs took during the wild overtime thriller.

Just a glance reveals that Detroit was in control all afternoon. Its Win Probability rarely dipped below 50 percent until late in regulation.

In fact, with just over four minutes to play, the Lions had a 95 percent chance of winning the game as the Texans faced 4th-and-7 in Lions territory.

Matt Schaub's 16-yard strike to Andre Johnson kept the afternoon alive for the Texans, who eventually tied the game and forced overtime.

In overtime, both teams had multiple chances to lock up a win. The Lions had better than a 65 percent chance to win on three separate possessions. They topped out at 88 percent with just under six minutes to play when they picked up a first down inside the Houston 30. That drive ended with a missed field goal by Jason Hanson.

The Texans responded by driving for the winning field goal with just over two minutes to play.

Houston's big contributors on the day also picked up the best WPA scores. WPA measures the amount a player adds to his team's win probability.

Schaub finished with 0.41 WPA for his efforts, but what's amazing is that Johnson was responsible for 0.38 points. That means that almost all the positive damage done by the Houston passing game could be attributed to one receiver.

For the game, Johnson finished with 188 yards receiving. All other Texans' receivers and tight ends put up just 74 yards combined.

For the record, that controversial Justin Forsett run? It was good for 0.17 WPA points. The Texans went from just a 17 percent chance of winning before the run to a 34 percent chance afterward.

While challenging it was the most memorable mistake Jim Schwartz made, it wasn't his worst. His decision to run three times inside the Houston 30 was what took his team from an 85 percent chance of winning to a 40 percent chance after the missed field goal.