Philip Rivers Stat Tracker: Week 2

Thanks to the nflFastR project and NFL NextGen Stats for the timely sources of data. Commentary will be brief but feel free to let me know in the comments that stats aren’t everything. (click charts for larger view)

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I’ve updated the charts that display standard deviations, to show +/- 2 std. dev. instead of 1. This will better highlight performances that are far above/below average.

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HOW WELL?

I’m introducing a new graph to show the depth of each throw and average yards per attempt both for the game and the trailing 10 passes. Philip Rivers yards per attempt was better than week 1 (8.6 vs 7.9), but he still relied on a lot of short throws to get that.

His EPA efficiency, however, was worse than last week, but still not bad. Some big 3rd down incompletions, a bad sack and of course the pick, depressed the numbers.

If T.Y. Hilton catches the touchdown and Mo Alie-Cox doesn’t bobble the pick, these numbers look very different, but I’m not measuring what-ifs.

Rivers’ key stats all hovered near NFL averages, except the net yards per dropback which has been a strength. Unfortunately, that is not translating into first downs and no offense can be successful without that.

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TO WHO?

Mo Alie-Cox caught some passes, but dropped an important one.

T.Y Hilton has been far below the NFL averages in production

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HOW FAR?

Average depth of target increased, which is good to see, but the average depth of completed passes is still below average.

Rivers’ 2 season TDs have been from very close to the goal line. Not only do I want to see more TDs, I want to see them from farther away, which is where good QBs add significant value.

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HOW FAST?

Rivers maintained his quick time to throw.

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HOW ACCURATE?

High accuracy again saved the passing game as Rivers is perfect on the season from within 5 yards.

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TO WHERE

While his efficiency beyond 10 yards improves, his passes between 0 - 10 yards are far below the average QB. This has to improve.

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GLOSSARY

Dropbacks: Attempted passes, Sacks or QB scrambles with QB spikes removed.

EPA per Dropback (EPA/db): For any given down, distance and field position, there is an average amount of points the team is expected to generate from that spot (EP). After the play the added EP (EPA) is calculated. EPA/db is the average of EPA for all QB dropbacks.

Passing Success Rate (PSR): This is the % of passes that were successful. Success is determined by dropbacks that have an EPA > 0. This is useful, as it evenly weights all dropbacks, so that extreme EPA events can’t bias the measure.

First Downs per Dropack (1st %): The percent of dropbacks that result in a first down.

Net Yards per Attempt (NY/A): Passing yards plus scramble yards minus sack yards divided by dropbacks.

Air Yards (ayd): The distance a pass travels through the air past the line of scrimmage. Passes behind the line of scrimmage have negative air yards. Batted down passes have 0 air yards.

Yards After Catch (YAC): The distance gained by a receiver after catching a pass.

Completion Percent Over Expected (cpoe): The percent of passes completed above expectation based on air yards, field placement and other variables. This is a proprietary stat provided by nflFastR.

Time to Throw (TtT): The number of seconds from snap to release on passing attempts.