With all the hoopla surrounding Josh Freeman and the back and forth of his season, as well as the attempts to place him historically against other quarterbacks, I figured a look at other quarterbacks in similar situations may help us get a better idea of where Freeman is as a player and where he may be headed. (To view all graphs, you can set your viewing to "Wide" as opposed to "Narrow" or you can click on links at bottom)
In the first edition of Part II, we looked at how completion percentages evolved among quarterbacks after their rookie year. To continue Part II, which will be broken out into several articles due to the amount of data, lets look at our same selected quarterbacks (minus Freeman as we have no season two data on him) and analyze another statistic to look at the strides, if any, that these quarterbacks made in the next two years (Years 2 and 3) of their starting careers.
Our goal is to project Freeman in years 2 and 3 with the data and results we find from analyzing all of our other quarterbacks. Lets get on with it, shall we?
As a refresher, I broke the quarterbacks into two categories, starters and backups. At this point in their careers (Years 2 and 3), all of our sampled quarterbacks were starting. We'll look at not only their numbers, but the numbers from the past 40 years of quarterbacks who also hit our playing time requirements. The same disclaimers still apply, but I think we're comfortable enough with them at this point to not have to list them one by one.
In this portion of Part II, we will continue to look at the accuracy component of a quarterback as well as analyzing the mindset and risk taking ability of a quarterback. We can only do this using data on hand, meaning we are only looking at yards per attempt, not how far the ball was thrown. If a quarterback throws a 50 yard bomb and the player is tackled immediately, that counts as 50 yards for that attempt. If a quarterback throws a 3 yard slant that goes for 50 yards, that also counts for 50 yards per attempt. This also does not account for the length of the throw. We'll also look at one of our new stats, YPA +, which ranks every player in regards to that particular season.
A few numbers that will be mentioned may seem a bit foreign to you, but let me give you a fairly simple run down. "Mean" is statistical talk for average. As far as standard deviations go, just think of it as variation. For our purposes, all you really need to be aware of is that in a normal distribution we can expect that approximately 68% of data will fall within one standard deviation of the mean and that approximately 95% of the data will fall within two standard deviations. We look at these numbers to essentially say that quarterback X should fall within this range based on historical data.
On the second component of Part II, Yards per Attempt, We'll run through the same drill as we did for completion percentage. I've assembled the data for not only our sample, but for all quarterbacks who, from 1970-2009, played 5+ games their rookie year, 10+ games their second year and 10+ games their third year. This will allow us to evaluate not only our sample, but to throw in a larger sample of NFL quarterbacks. With the parameters of our data, specifically the amount of games started, this tends to weed out the non-starters. This could impair our ability to predict Freeman, as those who didn't perform well enough to keep a job, won't be involved in our study. And those that didn't keep their job, I'd surmise that their data points are the ones that fell below average or acceptable.
Those quarterbacks (of which our group is included) featured a mean yards per attempt of 6.43 (standard deviation of .87). When we compare this to our "starter" and "backup" yards per attempt, which fall at 6.18 (1.36) and 6.45 (.89), we can see that they all are relatively similar with the backups having the top mean performance. The deviations for the starters is the largest while the other two groups are almost identical. Remember, this is rookie year only.
To give us an idea in visual form, lets turn to a scatterplot that will help demonstrate exactly where our groupings fell.
You can see the clustering in the 6.5 yards per attempt range. As you move away from that figure, the groupings become more sparse, indicating that fewer quarterbacks had higher or lower yards per attempt. This makes sense as our yards per attempt means were right around 6.5 and the deviations from that figure were not large.
To continue on with the YPA section, lets look at the chart of all of our data that we've compiled.
|Name||Category||YPA (1)||YPA (2)||YPA (3)||Year 1 to 2||Year 2 to 3||Year 1 to 3|
|Sample Set Mean||-||6.31||6.81||6.51||0.49||-0.29||0.20|
|Back up Mean||-||6.45||6.84||6.50||0.39||-0.34||0.05|
|St Dev All||-||1.15||0.92||0.84||-0.24||-0.07||-0.31|
These data points follow a similar pattern to our completion percentage table. The average move for NFL quarterbacks, our starters and backups is an increase in yards per attempt from year 1 to 2. Year 2 to 3 sees a slight decline in our groupings, but a slight increase for the NFL data we pulled (.15). Year 1 to 3 gives us a little bit of info based on our categorization. The average move up for NFL quarterbacks was .46 yards per attempt from year 1 to year 3. Our starters featured a move up of .35 yards per attempt while the backups only saw a move up of .05 yards. This is probably the first statistical difference we've seen between the two categories, though we are only looking at roughly a third of yard per attempt.
An interesting side note, that I'm not sure any of us can explain at this point is the seemingly larger move from years 1 to 2, which we see in bothcompletion percentage and yards per attempt, followed by a plateau or slight move down in years 2 to 3. We can guess that the move up has to do withgetting accustomed to playing in the NFL, familiarity with offense, speed and team mates, and once that connection is made, there may not be room for huge jumps again. It's also said that it takes approximately 4-5 years to "learn" an offense, so if/when we continue this series, we will be able to see if jumps were made in those years.
As you can see, the move in year 1 to year 2 seems to be an increase. In fact, the average movement from year 1 to 2 was .60 yards per attempt. A few quarterbacks, including both Manning brothers increased their yards per attempt number by over a yard when comparing their second year to rookie year. Again, we see a tight clustering and regression towards the 6.5 yards per attempt figure. While I do not know where the long term NFL mean stands, I'd reason a logical guess would be somewhere between 6.5 and 7.0 yards.
Now that we've seen our starters, our backups are next in line. Here are their figures, charted by year.
The backups feature a similar move, though not as drastic, seeing an average increase of .39 yards per attempt. This could be due to the fact that their original "starting point" was higher (6.45 to 6.18) as compared to the starters. I'll point out again the movement to the 6.5-7.0 range.
When looking at both groups, we can see that in year 2, in terms of mean numbers, all three groups are very similar (6.74, 6.81, 6.78). However, when looking at Year 3 averages. (6.89 to 6.51 to 6.53), our two groups underperformed the NFL average (1970-2009 based on criteria) by a decent margin. It seems that overall, there isn't much variance between our groups when looking at yards per attempt.
To illustrate what we discussed above, lets look at a quick graph that shows the means across the three year time horizon for our three groups.
Looking at the data presented here, it's difficult to see any differentiation between our two groups of starters and backups. We've been able to determine that the starters saw their yards per attempt increase by a higher figure over the first three years, but statistically, both groups end up within .02 yards of each other. This is somewhat expected. All of our selected quarterbacks were starters their first three years and it makes sense that they would fall close to the mean numbers. The differentiation should begin to occur as performances slip, leading to our backups being replaced.
To try and predict Freeman's performance is a tough task. We've established that there are just some variables we can't account for at this point. But by utilizing the past data we've accumulated, the analysis and a bit of statistical reasoning, we can place Freeman in a range, that while it seems pretty obvious, we have some statistical backing to it.
Using our two groupings and NFL numbers, we have a range for yards per attempt for years 2 and 3. For year 2, the range of one standard deviation (approx 68% of data will fall here) is 5.72 to 7.81 yards per attempt. This seems like a logical range and encapsulates where most of the data seems to fall (as expected). The two standard deviation range (95% of data), which should be a virtually certainty to have data fall in this range is 4.76 to 8.6 yards per attempt.
Year 3 stats sport a somewhat similar range. The first range comes in at 5.56 to 7.42. Again, we've seen most of the groupings fall int his range and we should be able to reasonably expect Freeman to fall in this range. If he does not, he is virtually certain to fall in the second range of 4.39 to 8.34 yards per attempt. Again, this last range is where we expect 95% of the data to fall in a normal distribution.
We've know covered two components of our statistical analysis with completion percentage and yards per attempt. We are starting to see some slight variations, but will have to continue to look at the data both in years 1 through 3 and forward to see if there is a common trait between backups and starters, and if we are able to put Freeman in any one of those categories at this point.
I encourage you to leave your thoughts below. If there is a certain statistic you have a question on, or want clarification, don't hesitate to ask. While I may not have the data on hand, if there is a question you have regarding any of these articles, drop it in the comments section.
In case any of the graphs above were not viewable for you, here are direct links to photobucket to use. Once you hit the link, the picture should show up. For optimal viewing, click the "Zoom In" button on the top left of picture.