September 7, 2010

QB Chart Glossary

DO: "Dead On." DOs are saved for truly excellent throws. Barring pass-interference penalties, these are basically always completions. Examples would include a long bomb right on target, or a difficult pass into tight coverage that squeezes through a narrow space.

Note: Almost all quick throws out of a 3-step drop or an immediate shotgun/pistol pass will end up as CA+ at best (see below). This includes slants, screens, etc.

CA: "Catchable." Run of the mill accurate throws. This is a very wide range of passes, which can range from well-thrown short passes, to longer throws which could be reasonably caught, but not easily. CA has three grades within it, which aren't charted separately in the final calculations, but are still useful as indicators of quality for individual passes:

- CA+: These are throws which are simple enough to not qualify for a DO, but are still done better than normal, often with some extra positive impact as a result. A good example would be a screen pass thrown so the running back can catch it in full stride and immediately make a cut to avoid a defender.
- CA: Standard catchable balls. Nothing out of the ordinary - a good college QB makes his living on these.
- CA-: These passes are clearly throws a receiver can catch, but the QB has made his life far more difficult due to a poor pass, usually with some level of negative impact as a result. A 5-yard out with the ball thrown low enough that the WR has to kneel to catch it, for example, costing potential YAC.

MA: "Marginal." There's a subset of throws that live on the boundary between 'catchable' and 'not catchable.' These encompass throws on which a WR has to make a nice play to reel in the ball, or very simple passes which are done so that a catch is no longer a guarantee. Choosing whether 'boundary' throws deserve a CA vs. MA, or an MA vs. IN, is often quite difficult. Generally, if the QB has received the 'harsher' grading on one pass, he'll receive the 'milder' grading on the next.

IN: "Inaccurate." These are throws that are just not catchable - though rarely a completion will still be made thanks to extraordinary effort by the WR. Relatively simple throws that require a receiver to make a circus catch will be given IN, as well as all passes which have no chance to be caught.

BR: "Bad Read." These are really, really bad. Throws that should not have been made due to excellent coverage, a lack of awareness of the situation, or inability to locate an open receiver all go here. Most interceptions that aren't due to tipped passes come from throws in the "Bad Read" category.

TA: "Throwaway." They are what we thought they were. These are passes which are clearly not intended to be caught since the quarterback can find no one open. A note - if the QB misses a wide-open receiver to throw the ball away, the play may be classified as a "Bad Read" instead. QB scrambles on obvious pass plays will go here too.

BA: "Batted." Balls which are deflected at the LOS. These are generally regarded as fluke occurences and are not held against the quarterback - though periodically they're caused by throwing the ball without the necessary loft.

PR: "Pressure." Here the QB doesn't have enough to to reasonably make a throw. Sacks may find their way here, although if the QB hesitates and does not throw despite being given time, that's either BR or TA. "Pressure" chartings are due to pass rushes only.

DSR: "Downfield Success Rate." A quarterback who completes a lot of quick outs and screen passes will have a very high ratio of 'catchable' to 'uncatchable' passes. This does not necessarily give an accurate representation of how well (or poorly) the QB has done, because most short pass plays are difficult to totally miss (oh how I hope and pray this is true). As such, the DSR aims to show how the quarterback does on pass plays not right at the line of scrimmage. Passes that are considered a "success" are DO or CA.

To make things clearer, I've included a sample chart for one game's worth of passes with a brief explanation.


 Opponent   DO   CA   MA   IN   BR   TA   BA   PR   DSR 
USC 2 14 (7) 1 (1) 2 1 2 4 (2) 3 50%

What the above means, is that for the imaginary game against USC, UCLA's quarterback had 2 passes that were basically perfect. He had 14 that fell somewhere in the 'catchable' range of good-but-not-great passes (again, no differentiation between CA+ and CA- at this point). However, of those catchable balls, a full 7 were extremely short passes - only half were down the field. He threw 1 marginal pass which was catchable, but only barely - also a screen play. He had 2 passes which had almost no chance of being caught. The QB made one extremely bad read, likely resulting in an interception (or a near-pick). He threw away 2 passes, had 4 batted down by linemen or blitzers (half of which were on screens), and had 3 plays on which the pressure gave him no chance to make a realistic pass (whether he got sacked, or actually got the pass off itself). There were 28 plays in which the QB dropped back to pass, but 10 were at the line of scrimmage. Of the remaining 18 passes, 9 were successful (2 DO, 7 CA), so 9 of his 18 passes down the field were at minimum reasonably good throws.

After each game, I'll add that game's totals into a running chart. For now, we'll call it the Chart of Hope - though I reserve the right to change that name to Chart of Despair depending on how the season goes.