Maurice Jones-Drew is a great running back.
Yes, I know. That's the kind of top-notch observation that keeps you coming back again and again to the AFC South blog.
This week, Advanced Stat of the Week will look at running back success rate. Success rate is one of the most important ways to judge the true effectiveness of a runner. Consider the following hypothetical runners.
Runner A has one 80-yard carry and nine carries for no gain. His stats are 80 yards, 10.0 yards per carry.
Runner B has eight 10-yard carries. Two of his carries came on 3rd-and-15. His stats are 80 yards, 10.0 yards per carry.
Runner C has 20 carries, for four yards each, but all his carries came on 3rd-and-3 or less. His stats are 80 yards, 4.0 yards per carry.
The back who helped his team win was the back who recorded the fewest yards per carry but had the most successful runs.
Success rate illustrates that a runner's ability to move the chains is his most important quality. "Boom and Bust" backs can be exciting, but carries for negative yards are drive-killers. Long runs thrill fans, but consistent gains are more valuable.
The Football Outsiders calculate success rate roughly in terms of the percentage of yards gained by the runner on each down. On first down, a back needs 40 percent of the yards his team needs for a first down. On second down, that jumps to 50 percent. On third and fourth down, a run is only successful if the back gets 100 percent of the necessary yards.
In terms of success rate, a three-yard run on 1st-and-10 is not successful. A three-yard run on 2nd-and-5 is successful. An eight-yard run on 3rd-and-10 is not successful. This sliding scale helps account for meaningless yards that a back accrues during the course of the game. Seven-yard gains on a draw on 4th-and-20 don't often mean much in the course of a football game, and success rate shows us that. A running back should be looking for a success rate north of 50 percent.
Success rate gives us yet another measure of just how terrific Jones-Drew is. By now, everyone knows that Jones-Drew led the Jags in rushing yards, despite playing in just six games.
What's amazing is how effective he was compared to the Jaguars' other running backs.
Jones-Drew not only out-rushed all other backs, but he did so with a solid success rate of 48 percent. Behind one of the worst lines in football and with teams loaded up against him, Jones-Drew managed to advance the ball.
Montell Owens also had a nice stretch late in the year. He only got carries between Weeks 13 and 16, but he averaged five yards a carry and had a brilliant success rate of 57 percent. That would have been second-best in the NFL if he had recorded enough carries to qualify.
On the flip side was Rashad Jennings. The next time anyone points to preseason numbers as a sign of things to come, bring up Jennings. With Jones-Drew holding out, Jennings was fantastic in the preseason, leading many to foolishly question if the Jaguars even needed their All-Pro runner.
Jennings was terrible in the regular season and his success rate of 38 percent ranked him 40th out of 41 qualified runners.
Without MoJo to move the chains, the Jaguars' offense collapsed. The 2011 Jaguars were bad with him, but the 2012 team was arguably the worst in the league without him.
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