Stats are funny things. Famously, with them you can find support for anything you like, citing anecdotally or compiling in a cherry picking way. But when the stats are proven to correspond to performance, the larger the sample size the clearer the picture becomes. Putting intelligent stats together and watching them over time makes important features stand out.
The Pro Football Focus premium stats - and I recommend them, there is a lot of digging that be done beyond even their excellent presentation, only $27 for a calendar year - try to bring out performance measures for each position so to isolate it as much as possible from all the other variables. They have some excellent QB stats, in particular those designed to make up for things like receiver drops, and take pocket pressures and distance in the air throws into consideration. What is best is that these numbers can be watched season to season, and a large portion of them are oriented towards one of the most important aspects of QB play: accuracy.
There has been a lot of talk about the quality of play of Mark Sanchez. Some people feel that he hasn't been given the tools to succeed, while others take note that this year he is having persistent problems, problems that he has had from the beginning. In the above I chart out the accuracy of Mark Sanchez over the course of his career thus far, through all the versions of the offense he has had at his disposal. What becomes clear is that Mark has not ever been an accurate QB at the NFL level, and in some ways he has been one of the worse accuracy QBs in the league since he came into it. In the above he has been in the bottom 5 of the league in 14 out of 16 qualifying statistical categories across 3 1/2 seasons, and last in 6 of those 16.
An Explanation of the Stats
The numbers are simply graphed out so you can see their relationship over time to each other. Where the data is available the rank Sanchez had for starting QBs is indicated in red. Because many of these stats are filtered to players with the top 50% of total dropbacks the number of QBs in a ranking vary from season to season. For this reason the number of QBs ranked below Sanchez are also listed in light blue. (Without using this filter Sanchez for instance finished 34th and 38th in Accuracy % in 2010 and 2009 respectively and I wanted to avoid ranks below even the number of teams.) This means that even though you may be ranked 23rd you could still be last because no other QBs made the cut off by dropbacks. So for stats like Adjusted QB rating, Accuracy %, Accuracy % under pressure Mark Sanchez is one of the worst (if not the worst) regularly starting NFL QBs in the league.
Completion % Under Pressure - simply the percent of completed passes when under pressure.
Completion % Under no Pressure - same as above, but no pressure. Here the QB is passing under relatively undisturbed situations.
% of Drop Backs Pressured - the percent of drop backs that are pressured. One could say that this indicates how often the QB has an uncomfortable pocket and also speaks to the quality of line and running back protection.
Accuracy % - Accuracy percentage includes drops counted as completions (and negates spikes and throwaways). This stat attempts to remove the penalty of poor handed receivers and attempts to isolate QBing throwing skills.
Accuracy % Under Pressure - Accuracy percentage under pocket pressure conditions.
Short Pass Completion % - basic completion % on passes traveling in the air either behind the LoS or up to 10 yards beyond the LoS, regardless of YAC.
Deep Pass Completion % - basic completion % on passes traveling 20 yards or more in the air, regardless of YAC.
Adjusted QB rating rank - this is the standard NFL QB passer rating, but tweaked to be a kind of "Ball in the Air" QB rating by counting drops as catches, negating throwaways and spikes, and discounting YAC (a favor to Sanchez I would think).
Aside from the aforementioned dreadfully low accuracy and rating stats throughout Sanchez's career - far lower than I thought given that things like drops are factored out and in some YAC is discounted as well (not a Sanchez strong suit), we see that the only thing that Sanchez does even at an average level is the deep pass completion percentage. But even that has to be qualified to some degree as this likely is not a pass that defenses have consistently defended as it has not been a significant weapon in play calling.
The other thing that sticks out a bit is that these percentages just are not changing much at all. A few points here, and few points there. We are getting a sense of a statistical "picture". Even things under more or less "ideal" QB circumstances (completion % under no pressure - high 50s, or for very short passes - high 60s) are strikingly low, not just for this year, but all years. No matter where we turn, whether it be to stats that eliminate drops or YAC, or stats that eliminate OL performance Sanchez seems to have proven himself to have one serious flaw, and that is the ability to throw the ball dependably with accuracy.
The one caveat in these stats that speak to his favor, and it is only a small one, is that since his rookie year when he was one of the least pressured QBs in the league (24 starting QBs faced pressure more frequently), he now has become the 15th most pressured QBs in the league nearly by definition league average. Sanchez has faced the reality of now having average QB protection whereas he once had the luxury of some of the best. This does him no favors as he has had the worst Accuracy % when under pressure in the league for the least 2 1/2 seasons (and as a rookie nearly the last). He is statistically terrible throwing the ball under pressure.
There are of course other factors that the season has become known for. The lack of a RB, a new OC, raw WRs, all of which may have prevented him from taking some kind of "leap". But what really surprised this otherwise naked eye is just how poor Sanchez in terms of accuracy has been before this, and consistently so, despite other positive qualities, in seasons when he had more of those benefits he wishes he had now. If you really strained there perhaps was a glimmer of hope (at least some progress...we are pushing it here) in his increase in % performance when not under pressure until this year before falling to rookie levels (climbing from 57.3 to 62.5, and then back to 58.3) or his very modest raise of short pass completion % from 67.4 to 70, before falling to 64.6. But as I mentioned above, even those levels are extremely low for a pressureless pocket or the short passing game. Given his lack of support this year he may have been deprived of a show of improvement that could have helped mask his deeper accuracy weaknesses, we can say that. Be that as it may, throwing the ball - with and without pressure - is a primary skill for a QB, and it is hard to debate against the reality these stats bring forward.
Would love to know what you see in these stats as well. Again, I highly recommend Pro Football Focus stats, they have even more interesting QB metrics. For those who think Sanchez compares favorably to Flacco, Ryan or Smith take a look at PFF and see where they rank and ranked. If the Jets lose next week sifting through stats looking for positives position by position might be one of the few Jet fan pleasures until 2013.