Obviously, a team has a better chance of landing a recruit if he lives nearby (or, in the case of Joe McKnight, they might be wishing they had stayed closer to home). In this blog I provide some evidence to support a claim I made in part 1 that increasing population increased the talent pool and, therefore, led to better football teams.
I picked 8 states more or less at random. I tried to include states from a variety of regions, with a variety of sizes and that have experienced a variety of population trends. I have included both Nebraska and Oklahoma, and, honestly, I don't know why.
Ratings come from Soren Sorenson, who you will find listed in the Statistics Hall of Fame. I have added 5000 to all scores so that they are all positive (Sorenson's system ranges from -4000 to +4000, +or- a thousand). Population data is drawn from the Census. Census data is collected every ten years and I have used my own estimates to fill in the gaps.
I have looked at states as a whole, adding together the ratings of all teams in that state, because teams in the same state recruit for players in the same talent pool. For now, I am ignoring population growth in the region (e.g. Georgia benefits from population growth in Florida), and characteristics of the population (e.g. old people in Arizona don't play football), but some day I will look at those issues in more detail.
So, first we begin in 1950.
The 8 states are Nebraska and Oklahoma, which I already mentioned, Florida, Arizona, New York, Indiana, North Carolina and Alabama. The graphic on the left shows the teams as they were ranked in 1950, color coded by state. Florida State, UCF, USF, and Buffalo did not have D 1 programs at the time (or, in some cases, did not have a football team, or just started admitting boys to the school).
This chart is important because, from here on, I will be focusing on indexed values for the state, so that indexed value will always reference back to this starting point. For example, 1950 was a good year for Oklahoma and Army (perhaps the two best teams in the country). This will be important to keep in mind.
This next chart demonstrates an important principle as well. This compares the percent of the total points held by a state (with their scores added together) of all the points available against the percent of the US population in that state. So, New York, despite Army's success, was under-performing. Anyone who has been to a high school football game in Dallas and in Rochester knows why this is happening. It shouldn't surprise anyone that Oklahoma performed the best giving their population size. Alabama was facing a unique challenge in segregation. It would be another 20 years before Sam Bam Cunningham would convince Bear Bryant to integrate, allowing Alabama to dip much deeper in its talent pool.
The population of most states would grew over the next 50 years, but some grew much faster than others. Florida and Arizona are good examples of states that blew up in terms of population, while New York stagnated.
In the following charts, I present data for each state in terms of their performance and their population over the 5 decades from 1950 to 2000. The black line is the team's performance. It is a running four year average which I use under the assumption that players from a cohort will play for a team for four years. The red line is the indexed population, where 100 is equal to the population in 1950. The blue line is based on the same principle, but represents the percent of the US population represented by that state, so that if a team's population is growing slower, but slower than the entire US, the blue line will fall but the red line will rise. The red line, therefore, represents the real talent pool and the blue line the relative talent pool, and because teams are good relative to each other, we should focus on the blue line. (You can click the charts to see a bigger version.)
Nebraska had some kicking teams in the 70's and the mid to late 90's, which shows up in their chart. The population as a percent of the US population was actually going down, but Nebraska kept spitting out world class teams. It makes me think that Osborne may have been a much better coach than we give him credit for. Arizona's performance isn't improving with its rapidly growing population. I think two things are at issue. First, Arizona doesn't have as strong of a football culture as the rest of the South and, second, Arizona's programs might be experiencing a bit of a lag.
I was a little surprised to see how well Indiana fits the pattern. Notre Dame has a unique advantage to recruit nationally and should be able to overcome general demographic shifts. Notre Dame claims their challenges are rooted in high academic standards, so I guess I'll have to look at that claim another day.
Alabama has been generally outplaying its population since the 50's but, like all the others, its performance is generally falling with the decline in its relative population size. The effect of integration on performance is still a little unclear, but something I will definitely look at more closely in the future.
But the overall results from this little experiment are clear--population trends in a region definitely effect the performance of that regions teams. The black lines tend to go where ever the blue lines are going. It also shows that we can't ignore culture, quality of coaches and the power of programs to attract players from long distances.
BPR | A system for ranking teams based only one wins and losses and strength of schedule. See BPR for an explanation. |
EPA (Expected Points Added) | Expected points are the points a team can "expect" to score based on the distance to the end zone and down and distance needed for a first down, with an adjustment for the amount of time remaining in some situations. Expected points for every situation is estimated using seven years of historical data. The expected points considers both the average points the offense scores in each scenario and the average number of points the other team scores on their ensuing possession. The Expected Points Added is the change in expected points before and after a play. |
EP3 (Effective Points Per Possession) | Effective Points Per Possession is based on the same logic as the EPA, except it focuses on the expected points added at the beginning and end of an offensive drive. In other words, the EP3 for a single drive is equal to the sum of the expected points added for every offensive play in a drive (EP3 does not include punts and field goal attempts). We can also think of the EP3 as points scored+expected points from a field goal+the value of field position change on the opponent's next possession. |
Adjusted for Competition | We attempt to adjust some statistics to compensate for differences in strength of schedule. While the exact approach varies some from stat to stat the basic concept is the same. We use an algorithm to estimate scores for all teams on both sides of the ball (e.g., offense and defense) that best predict real results. For example, we give every team an offensive and defensive yards per carry score. Subtracting the offensive score from the defensive score for two opposing teams will estimate the yards per carry if the two teams were to play. Generally, the defensive scores average to zero while offensive scores average to the national average, e.g., yards per carry, so we call the offensive score "adjusted for competition" and roughly reflects what the team would do against average competition |
Impact | see Adjusted for Competition. Impact scores are generally used to evaluate defenses. The value roughly reflects how much better or worse a team can expect to do against this opponent than against the average opponent. |
[-] About this table
Includes the
top 180 QBs by total plays
Total <=0 | Percent of plays that are negative or no gain |
Total >=10 | Percent of plays that gain 10 or more yards |
Total >=25 | Percent of plays that gain 25 or more yards |
10 to 0 | Ratio of Total >=10 to Total <=0 |
Includes the
top 240 RBs by total plays
Total <=0 | Percent of plays that are negative or no gain |
Total >=10 | Percent of plays that gain 10 or more yards |
Total >=25 | Percent of plays that gain 25 or more yards |
10 to 0 | Ratio of Total >=10 to Total <=0 |
Includes the
top 300 Receivers by total plays
Total <=0 | Percent of plays that are negative or no gain |
Total >=10 | Percent of plays that gain 10 or more yards |
Total >=25 | Percent of plays that gain 25 or more yards |
10 to 0 | Ratio of Total >=10 to Total <=0 |
Includes
the
top 180 players by pass attempts)
3rdLComp% |
Completion % on 3rd and long (7+
yards) |
SitComp% |
Standardized completion % for
down and distance. Completion % by down and distance are weighted by
the national average of pass plays by down and distance. |
Pass <=0 | Percent of pass plays that are negative or no gain |
Pass >=10 | Percent of pass plays that gain 10 or more yards |
Pass >=25 | Percent of pass plays that gain 25 or more yards |
10 to 0 | Ratio of Pass >=10 to Pass<=0 |
%Sacks |
Ratio of sacks to pass plays |
Bad INTs |
Interceptions on 1st or 2nd down
early before the last minute of the half |
Includes the top 240 players by carries
YPC1stD |
Yards per carry on 1st down |
CPCs |
Conversions (1st down/TD) per
carry in short yardage situations - the team 3 or fewer yards for a 1st
down or touchdown |
%Team Run |
Player's carries as a percent of team's carries |
%Team RunS |
Player's carries as a percent of team's carries in short
yardage situations |
Run <=0 |
Percent of running plays that
are negative or no gain |
Run >=10 |
Percent of running plays that
gain 10 or more yards |
Run >=25 | Percent of running plays that gain 25 or more yards |
10 to 0 | Ratio of Run >=10 to Run <=0 |
Includes the top 300 players by targets
Conv/T 3rd | Conversions per target on 3rd Downs |
Conv/T PZ | Touchdowns per target inside the 10 yardline |
%Team PZ | Percent of team's targets inside the 10 yardline |
Rec <=0 | Percent of targets that go for negative yards or no net gain |
Rec >=10 | Percent of targets that go for 10+ yards |
Rec >=25 | Percent of targets that go for 25+ yards |
10 to 0 | Ratio of Rec>=0 to Rec<=0 |
Includes the top 300 players by targets
xxxx | xxxx |
...
Includes players with a significant number of attempts
NEPA | "Net Expected Points Added": (expected points after play - expected points before play)-(opponent's expected points after play - opponent's expected points before play). Uses the expected points for the current possession and the opponent's next possession based on down, distance and spot |
NEPA/PP | Average NEPA per play |
Max/Min | Single game high and low |
Includes players with a significant number of attempts
NEPA | "Net Expected Points Added": (expected points after play - expected points before play)-(opponent's expected points after play - opponent's expected points before play). Uses the expected points for the current possession and the opponent's next possession based on down, distance and spot |
NEPA/PP | Average NEPA per play |
Max/Min | Single game high and low |
Adjusted | Reports the per game EPA adjusted for the strength of schedule. |
Defensive Possession Stats
Points/Poss | Offensive points per possession |
EP3 | Effective Points per Possession |
EP3+ | Effective Points per Possession impact |
Plays/Poss | Plays per possession |
Yards/Poss | Yards per possession |
Start Spot | Average starting field position |
Time of Poss | Average time of possession (in seconds) |
TD/Poss | Touchdowns per possession |
TO/Poss | Turnovers per possession |
FGA/Poss | Attempted field goals per possession |
%RZ | Red zone trips per possession |
Points/RZ | Average points per red zone trip. Field Goals are included using expected points, not actual points. |
TD/RZ | Touchdowns per red zone trip |
FGA/RZ | Field goal attempt per red zone trip |
Downs/RZ | Turnover on downs per red zone trip |
Defensive Play-by-Play Stats
EPA/Pass | Expected Points Added per pass attempt |
EPA/Rush | Expected Points Added per rush attempt |
EPA/Pass+ | Expected Points Added per pass attempt impact |
EPA/Rush+ | Expected Points Added per rush attempt impact |
Yards/Pass | Yards per pass |
Yards/Rush | Yards per rush |
Yards/Pass+ | Yards per pass impact |
Yards/Rush+ | Yards per rush impact |
Exp/Pass | Explosive plays (25+ yards) per pass |
Exp/Rush | Explosive plays (25+ yards) per rush |
Exp/Pass+ | Explosive plays (25+ yards) per pass impact |
Exp/Rush+ | Explosive plays (25+ yards) per rush impact |
Comp% | Completion percentage |
Comp%+ | Completion percentage impact |
Yards/Comp | Yards per completion |
Sack/Pass | Sacks per pass |
Sack/Pass+ | Sacks per pass impact |
Sack/Pass* | Sacks per pass on passing downs |
INT/Pass | Interceptions per pass |
Neg/Rush | Negative plays (<=0) per rush |
Neg/Run+ | Negative plays (<=0) per rush impact |
Run Short | % Runs in short yardage situations |
Convert% | 3rd/4th down conversions |
Conv%* | 3rd/4th down conversions versus average by distance |
Conv%+ | 3rd/4th down conversions versus average by distance impact |
Offensive Play-by-Play Stats
Plays | Number of offensive plays |
%Pass | Percent pass plays |
EPA/Pass | Expected Points Added per pass attempt |
EPA/Rush | Expected Points Added per rush attempt |
EPA/Pass+ | Expected Points Added per pass attempt adjusted for competition |
EPA/Rush+ | Expected Points Added per rush attempt adjusted for competition |
Yards/Pass | Yards per pass |
Yards/Rush | Yards per rush |
Yards/Pass+ | Yards per pass adjusted for competition |
Yards/Rush+ | Yards per rush adjusted for competition |
Exp Pass | Explosive plays (25+ yards) per pass |
Exp Run | Explosive plays (25+ yards) per rush |
Exp Pass+ | Explosive plays (25+ yards) per pass adjusted for competition |
Exp Run+ | Explosive plays (25+ yards) per rush adjusted for competition |
Comp% | Completion percentage |
Comp%+ | Completion percentage adjusted for competition |
Sack/Pass | Sacks per pass |
Sack/Pass+ | Sacks per pass adjusted for competition |
Sack/Pass* | Sacks per pass on passing downs |
Int/Pass | Interceptions per pass |
Neg/Run | Negative plays (<=0) per rush |
Neg/Run+ | Negative plays (<=0) per rush adjusted for competition |
Run Short | % Runs in short yardage situations |
Convert% | 3rd/4th down conversions |
Conv%* | 3rd/4th down conversions versus average by distance |
Conv%+ | 3rd/4th down conversions versus average by distance adjusted for competition |
Offensive Possession Stats
Points/Poss | Offensive points per possession |
EP3 | Effective Points per Possession |
EP3+ | Effective Points per Possession adjusted for competition |
Plays/Poss | Plays per possession |
Yards/Poss | Yards per possession |
Start Spot | Average starting field position |
Time of Poss | Average time of possession (in seconds) |
TD/Poss | Touchdowns per possession |
TO/Poss | Turnovers per possession |
FGA/Poss | Attempted field goals per possession |
Poss/Game | Possessions per game |
%RZ | Red zone trips per possession |
Points/RZ | Average points per red zone trip. Field Goals are included using expected points, not actual points. |
TD/RZ | Touchdowns per red zone trip |
FGA/RZ | Field goal attempt per red zone trip |
Downs/RZ | Turnover on downs per red zone trip |
PPP | Points per Possession |
aPPP | Points per Possession allowed |
PPE | Points per Exchange (PPP-aPPP) |
EP3+ | Expected Points per Possession |
aEP3+ | Expected Points per Possession allowed |
EP2E+ | Expected Points per Exchange |
EPA/Pass+ | Expected Points Added per Pass |
EPA/Rush+ | Expected Points Added per Rush |
aEPA/Pass+ | Expected Points Allowed per Pass |
aEPA/Rush+ | Expected Points Allowed per Rush |
Exp/Pass | Explosive Plays per Pass |
Exp/Rush | Explosive Plays per Rush |
aExp/Pass | Explosive Plays per Pass allowed |
aExp/Rush | Explosive Plays per Rush allowed |
BPR | A method for ranking conferences based only on their wins and losses and the strength of schedule. See BPR for an explanation. |
Power | A composite measure that is the best predictor of future game outcomes, averaged across all teams in the conference |
P-Top | The power ranking of the top teams in the conference |
P-Mid | The power ranking of the middling teams in the conference |
P-Bot | The power ranking of the worst teams in the conference |
SOS-Und | Strength of Schedule - Undefeated. Focuses on the difficulty of going undefeated, averaged across teams in the conference |
SOS-BE | Strength of Schedule - Bowl Eligible. Focuses on the difficulty of becoming bowl eligible, averaged across teams in the conference |
Hybrid | A composite measure that quantifies human polls, applied to converences |
Player Game Log
Use the yellow, red and green cells to filter values. Yellow cells filter for exact matches, green cells for greater values and red cells for lesser values. By default, the table is filtered to only the top 200 defense-independent performances (oEPA). The table includes the 5,000 most important performances (positive and negative) by EPA.
Use the yellow, red and green cells to filter values. Yellow cells filter for exact matches, green cells for greater values and red cells for lesser values. By default, the table is filtered to only the top 200 defense-independent performances (oEPA). The table includes the 5,000 most important performances (positive and negative) by EPA.
EPA | Expected points added (see glossary) |
oEPA | Defense-independent performance |
Team Game Log
Use the yellow, red and green cells to filter values. Yellow cells filter for exact matches, green cells for greater values and red cells for lesser values.
Use the yellow, red and green cells to filter values. Yellow cells filter for exact matches, green cells for greater values and red cells for lesser values.
EP3 | Effective points per possession (see glossary) |
oEP3 | Defense-independent offensive performance |
dEP3 | Offense-independent defensive performance |
EPA | Expected points added (see glossary) |
oEPA | Defense-independent offensive performance |
dEPA | Offense-independent defensive performance |
EPAp | Expected points added per play |
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