Monday, August 9, 2010

Something Funny Happened On The Way To A Trend

The easiest posts to write are the ones that just dissect a bunch of numbers. They can be time consuming but the actual reporting part is easy. 'hey guys, look what I found, pretty much what we all already knew anyway'.

But sometimes the numbers actually throw enough of a curve to make the game worthwhile.

So over a couple of days I rooted around with numbers from young starting quarterbacks.I am trying to determine the degree and predictability of improvement from one season to the next.

I took the group of all quarterbacks from 2000 - 2008 who had their first starting season in one of their first three years in the NFL, and then took the subsequent year for comparison. There were 13 rookie quarterbacks and 16 veterans - quarterbacks who had played at least one year without starting. The fewest starts I considered were Aaron Brooks' 5 starts in 2000.

I looked at Y/A, TD%, INT%, Comp % and AY/A.

So looking at the whole group the results were pretty unsurprising, or if they were surprising it was in the underwhelming improvement that the group of quarterbacks tend to make from their first starting year to their second. In all cases the standard deviation was much larger than the improvement, usually many times larger. In other words, the performance of year one held very little correlation to either the statistics or range of year two. The only significant gain was in completion %, an average of 2.3%. Y/A was just under +1%. Every other gain - while positive - was less than 0.1%.

The ranges were so great that actually putting numbers to them seems kind of pointless.

So since this wasn't telling me a thing I decided to break it out by true rookie seasons versus more seasoned players getting their first starting jobs. My eyeballs had already told me that rookie starters tended to have significant jumps in their second seasons.

To put it mildly I was right.

While the standard deviations remained huge, far too large to generate useful projections, the actual change in the overall trends was stunning.

Second year quarterbacks who had started as rookies saw huge jumps in all statistics. On average TD% +0.6%, INT% - 0.5%, Comp % +5.2%. Of all rookies only 2 had declines in Comp% and those two were the two with the highest averages their rookie seasons, Ben Roethlisberger and Matt Ryan. Roethlisberger's Y2 Comp % remained well above average while Ryan's dipped slightly below.

Okay, but here's the cool part. If the overall group so almost no gain from Y1 to Y2 and the rookies saw huge gains from Y1 to Y2 what about the others? They were worse in every single category. Some declines were almost zero but there were fairly large declines in TD% (-0.4%) and INT % (+0.3%).

So what does this mean? That regardless of whether a player plays his rookie season, he virtually becomes the entire quarterback that he will be that year and that his second year statistics will accurately reflect his career expectations.

Okay, this is only sort of true. There is one more thing to look at and that is what kind of incremental gains are made by a player's 3rd or 4th starting season. By then the players who fail as starters are no longer starting and we can get a better idea of what kind of progress a successful quarterback makes from his 1st to 4th year.


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