NFL Wrapup: APR Pick Reliability

2009 Navigation Links

Read this for a description of APR

Introduction

The following is an analysis of APR pick reliability for regular season games.

APR new margin power vs. classic margin power

You may remember at the beginning of the season I announced that I would be using a new margin power function for the APR power rankings this year. APR's picks for this year finished at 152-88. This turns out to be 6 picks weaker than the original 'classic' margin function for the same 2009 games.

The new and classic versions of APR were actually mostly in agreement on game picks; they only picked 8 games differently (correct picks are shown in bold):

Week	Game				Pick (current)	Pick (classic)
3	Falcons	10,	Patriots	26	Falcons	Patriots
4	Jets	10,	Saints	24	Jets	Saints
5	Patriots	17,	Broncos	20	Patriots	Broncos
10	Bills	17,	Titans	41	Bills	Titans
11	Chargers	32,	Broncos	3	Broncos	Chargers
12	Giants	6,	Broncos	26	Broncos	Giants
12	Steelers	17,	Ravens	20	Steelers	Ravens
14	Redskins	14,	Raiders	13	Raiders	Redskins

Over the course of the season, I've become increasingly dissatisfied with the new margin power function; this tends to confirm my suspicion that it's not really an improvement.

APR: Home vs Visitor

Here's the breakdown of pick accuracy for picking the visiting or home teams.

	Visitor Won	Home Won	Total
Picked Right	66	86	152
Picked Wrong	37	51	88
Total	103	137	240

APR picked the home team to win 123 times (86+37), again noticably less than the 137 home teams that did win.

As with last year, this indicates that something needs to be changed so that the home team is picked more often. This year, I think I know what that change needs to be: each team needs to have separate home and away power rankings, and the games picked according to the appropriate power.

If you look at the regular season standings, there are some teams that have a noticable difference between home and road records:

Team	Home Record	Road Record	Difference
Patriots	8-0	2-6	6
Vikings	8-0	4-4	4
49ers	6-2	2-6	4
Ravens	6-2	3-5	3
Steelers	6-2	3-5	3
Falcons	6-2	3-5	3
Bears	5-3	2-6	3
Seahawks	4-4	1-7	3

I will be very surprised if separating power rankings into home and away categories doesn't yeild at least some improvement in pick reliability.

APR vs. Pythagorean Projection

For week 1 of the season, I posted game picks based on the Pythagorean projections from last year. The Pythagorean picks for this year were 164-92-0 (64.1%), which beats APR (and even APR classic) this year. A 64.1% successful pick rate is best Pythagorean Projection has done at least since 1993 (see results for previous years here, along with an important update).

Conclusions

APR continues to be a work in progress. For next year, I will implement the home/away power rankings for game picks (the weekly power ranking posts will still show a combined power ranking, though).

I'm going to abandon the current margin weight function, either in favor of the classic function, or something better (if I can find something better).

I'm also going to adopt the Pythagorean Projection pick method for week 1 games, so that APR can pick the full season of games.

NFL: Rate of tie and overtime games

Just about two weeks ago, I posted some data analyizing the rate of playoff games that went to overtime from 1970 to 2009. That data shows a marked increase in overtime playoff games since 1999. This post takes a look at the rate of tie and overtime games for the history of the league.

How the data was gathered

• I used the data as given on pro-football-reference.com.

• Only NFL games were considered. This means the first two APFA seasons, the AAFC and AFL games are not included in this data.

• The number of teams in the league and number of games played each season has, of course, fluctuated. Therefore, the numbers for each season are presented as a percentage of games played, in order to make them as comparable as possible season-to-season.

The Data

Here is a graph of the result. The red line represents tie games, the blue line represents overtime games.

Click picture to open full size image

Comments:

• There's a surprising amount of season-to-season variation, even in the modern era, of games that are tied after four quarters.

• The rate of overtime playoff games from 1970 to 1998 (3.7%) is at the lower range of regular season overtime games during that era; the rate of overtime playoff games 1998 to 2009 (14.3%) is well over the rate of regular season overtime games.

• There doesn't seem to be an increase in the number of overtime games in the regular season since 1999. Certainly nothing as dramatic as what has happened in the playoffs.

Interesting stuff I found while looking at the data:

• The two highest-scoring tie games were both in the AFL: Raiders 43, Patriots 43 (1964), and Bills 38, Broncos 38 (1960). The highest-scoring tie games in the NFL is 35-35, which happened five times (so far), including once in the AFL.

• The team with the most ties in a single season is the NFL Champion 1932 Chicago Bears, who posted a record of 7-1-6. No other team has more than 4 ties in a season, and no team has had more than 3 in a season since 1932.

NFL Super Bowl Power Rankings

2009 Navigation Links
Read this for a description of APR.

Rank	Team	W-L	Power Index	This week
1 (↑2)	New Orleans Saints	16-3	6.8776 (LW × 1.156)	won by 14 at Colts
2 (-)	Carolina Panthers	8-8	6.3478 (LW × 1.054)	Bye
3 (↑2)	Dallas Cowboys	12-6	5.9514 (LW × 1.033)	Bye
4 (-)	New York Jets	11-8	5.8160 (LW × 0.984)	Bye
5 (↓4)	Indianapolis Colts	16-3	5.6848 (LW × 0.907)	lost by 14 vs Saints
6 (-)	Minnesota Vikings	13-5	5.5107 (LW × 1.021)	Bye
7 (-)	New England Patriots	10-7	5.2420 (LW × 0.999)	Bye
8 (-)	San Diego Chargers	13-4	5.1236 (LW × 1.001)	Bye
9 (-)	Atlanta Falcons	9-7	4.9684 (LW × 1.018)	Bye
10 (-)	Green Bay Packers	11-6	4.8731 (LW × 1.005)	Bye
11 (↑2)	Philadelphia Eagles	11-6	4.7361 (LW × 1.016)	Bye
12 (↓1)	Baltimore Ravens	10-8	4.6672 (LW × 0.991)	Bye
13 (↓1)	Buffalo Bills	6-10	4.5583 (LW × 0.974)	Bye
14 (-)	Houston Texans	9-7	4.4101 (LW × 0.986)	Bye
15 (-)	Pittsburgh Steelers	9-7	4.3174 (LW × 0.999)	Bye
16 (-)	Arizona Cardinals	11-7	4.0303 (LW × 1.011)	Bye
17 (-)	Miami Dolphins	7-9	3.7308 (LW × 1.002)	Bye
18 (↑2)	New York Giants	8-8	3.6756 (LW × 1.023)	Bye
19 (-)	Cincinnati Bengals	10-7	3.6120 (LW × 0.996)	Bye
20 (↓2)	Tennessee Titans	8-8	3.5815 (LW × 0.985)	Bye
21 (-)	Denver Broncos	8-8	3.4926 (LW × 1.001)	Bye
22 (-)	San Francisco 49ers	8-8	3.3890 (LW × 0.997)	Bye
23 (↑2)	Tampa Bay Buccaneers	3-13	3.1991 (LW × 1.052)	Bye
24 (↓1)	Cleveland Browns	5-11	3.1891 (LW × 0.992)	Bye
25 (↓1)	Chicago Bears	7-9	3.1715 (LW × 1.007)	Bye
26 (-)	Jacksonville Jaguars	7-9	2.9492 (LW × 0.976)	Bye
27 (-)	Kansas City Chiefs	4-12	2.7491 (LW × 0.999)	Bye
28 (-)	Washington Redskins	4-12	2.6800 (LW × 1.024)	Bye
29 (-)	Oakland Raiders	5-11	2.3928 (LW × 1.000)	Bye
30 (-)	Seattle Seahawks	5-11	1.9869 (LW × 0.998)	Bye
31 (-)	St. Louis Rams	1-15	1.4323 (LW × 1.012)	Bye
32 (-)	Detroit Lions	2-14	1.4049 (LW × 1.007)	Bye

Comments

• The Saints get a big boost from their 2-score win and retake the top spot.

• The top 10 looks pretty reasonable... except for the Panthers at #2. They did have some good wins to end the season. But how that translates into a death-grip on the #2 spot, I can't say.

• The Colts seemed to have a bit of a down year on offense, scoring 416 points in the regular season. Except for last year (when Manning had knee issues), you have to go back to 2001 to find a year with lower production.

  416 is only 9 points off their total for 2006, when they won Super Bowl XLI, but they faced a much weaker opponent then, too.

  There's already talk of the Colts as favorites to win the next Super Bowl. One thing to watch next season will be their point totals. The NFC is likely to send another high-scoring team to the Super Bowl next year, and if the Colts aren't on pace to score at least 430 points over the regular season, they could end up short again.

Epilogue

That's the end of another season, and the final power ranking until September. There will be some more season wrapup posts in the next week or so, and at least a couple historical data posts (I've got the regular season tie frequency post nearly ready).

But after next week, FSPI will be pretty quiet until August or so (you can check out what it was like last year by looking at the "Blog Archive" links on the left).

Once again, thanks for reading. See you in September.

NFL Super Bowl Pick Results

2009 Navigation Links

Pick results for the Super Bowl.

Saints (SRS) vs. Colts (APR, Line)

The Saints really played a masterful game. They took chances when they needed to, kept the game within reach, and played to their strong passing game.

The Colts, on the other hand... of course, Manning's pick-6 comes up big. That looked to me like just an awful throw. But the real problem was clock management. They needed to have a quick score game plain against the Saints. Instead, their first two second-half drives used 11:48 off the clock and only got them 7 points.

Even if Manning hadn't thrown that interception, if the Colts had held on to the ball and tied the game, the Saints likely would have had two minutes to drive for a go-ahead score, with little or no time left for the Colts to respond.

It almost seems like the Colts were using the same "establish a lead and sit on the ball" strategy that they used against the Ravens and Jets. But that just doesn't work when your oppoent has a quarterback like Drew Brees.

Standings:

	This Week	Overall
APR	0-1	5-6
SRS	1-0	6-5
Line	0-1	8-3
Unanimous	0-0	3-1

The final power rankings to come, plus a few more season wrap-up posts.

NFL Wrapup: APR Picks by team

Record	Teams	Comments
14-1	Rams	The Rams were not picked to beat the Lions in week 8.
13-2	Chargers
12-3	Lions, Colts, Buccaneers, Bears	The Bears were a pretty bad team this year, especially for making it to 7 wins. APR had them ranked in the bottom 10 from week 9 to the end of the season.
11-4	Vikings	APR never picked against the Vikings.
10-5	Seahawks, Saints, Redskins, Patriots, Packers, Giants, Eagles, Chiefs, Bengals	I'm surprised APR did this well on the Patriots considering the gap between their home record (8-0) and road record (2-6).
9-6	Titans, Ravens, Falcons, Cowboys, Cardinals, Browns, Bills	16 teams picked 9-6 or worse; same as last year.
8-7	Raiders, Panthers, Jets, Broncos, 49ers	The 49ers were another team with a big difference between their home record (6-2) and road record (2-6)
7-8	Texans, Jaguars, Dolphins	How much does a crowd matter to home field advantage? In spite of their often empty stands, the Jaguars were another team did a lot better at home (5-3) than on the road (2-6).
4-11	Steelers	How do you pick a team like this? Four of their wins came against playoff teams (Chargers, Vikings, Packers, and Ravens), while three of their losses came against some of the worst teams in the league (Chiefs, Browns, and Raiders).

Update: I should make clear that this is for regular season games only (weeks 2-17).

NFL Wrapup: Pythagorean Projection vs Reality

Last summer, I did a series of posts on Pythagorean Projection (Part I, Part II, Part III, Part IV). As a follow-up to Part III, I present the Projected Wins for 2009 versus Actual Wins.

Note that the format for this table is slightly different than what I used in Part II. Here, the projection was used as a baseline, so a positive difference means a team exceeded its projected wins; a negative difference means a team fell short of its projected wins.

Team	Actual	Proj.	Diff	Comment
Jets	9	9.2	-0.2	New HC, QB
Eagles	11	11.3	-0.3
Seahawks	5	5.4	-0.4	New HC
Chiefs	4	4.4	+0.4	New HC, QB
Raiders	5	4.6	+0.4
Browns	5	4.4	+0.6	New HC
Patriots	10	10.6	-0.6	Brady back
Falcons	9	9.7	-0.7
Lions	2	2.8	-0.8	New HC, QB
Jaguars	7	6.2	+0.8
49ers	8	6.9	+1.1
Rams	1	2.6	-1.6	New HC, injuries
Bears	7	8.7	-1.7	New QB
Texans	9	7.3	+1.7
Broncos	8	6.2	+1.8	New HC, QB
Bills	6	7.8	-1.8
Dolphins	7	8.8	-1.8	Injuries
Cardinals	10	8.0	+2.0
Packers	11	8.9	+2.1	New defense
Panthers	8	10.1	-2.1	Jake Delhomme
Vikings	12	9.2	+2.8	New QB
Steelers	9	11.8	-2.8	Troy Polamalu hurt
Colts	13	10.1	+2.9	Manning healthy all year
Chargers	13	10.1	+2.9
Ravens	9	11.9	-2.9
Redskins	4	7.0	-3.0
Cowboys	11	7.9	+3.1
Giants	8	11.3	-3.3	Eli injured
Saints	13	9.5	+3.5
Titans	8	12.1	-4.1	No more Haynesworth
Buccaneers	3	9.0	-6.0	New HC, QB
Bengals	10	3.2	+6.8	Healthy Carson Palmer

Broken down into the range used in Part I, we have:

Range		# of Teams	% of 32	Classification
0	≤δ≤ 2	17	53.1%	Reasonably Close
2	<δ≤ 4	12	37.5%	Moderately Close
4	<δ≤ 8	3	9.4%	Wrong
8	<δ	0	0.0%	Yikes!

(Note that in Part I, the difference was expressed in winning percentage; here it is expressed in games won in a 16-game season.)

Comments

• The teams are sorted by the magnatude of difference; teams that came very close to their projected wins are at the top, teams further away come further down the table.

• In 2008 (c.f. Part II), 8 teams (25%) finished at least 5 games away from their projected win total, which (as I said) seemed likely to be an outlier year. Here we see teams much closer: only two finished more than 5 games away from their projected wins total.

• There's also a case to be made for more gradual coaching changes. The Cardinals 2-game improvement (which could've been 3, if they had had something to play for in week 17), can be attributed to continuing improvements under Coach Whisenhunt. While the Redskins 3-game fall-off might be attributed to Coach Zorn losing his squad.

• Those two or three extra wins that Favre (presumably) brought to the Vikings might not seem like a big deal out of context, but (this year) they're the difference between the #2 seed and being the last wildcard (or maybe eliminated in favor of the Falcons or some other team)

NFL Wrapup: Significance of the first two games

Last September, I did a post on how the first two games of the season correlated to final standings. As a follow-up, here's how the 2009 season turned out:

	Team	Standing	Note
WW	Colts	14- 2
Teams	Saints	13- 3
(9)	Vikings	12- 4
	Jets	9- 7
	Ravens	9- 7
	Falcons	9- 7
	Broncos	8- 8
	Giants	8- 8
	49ers	8- 8	avg wins: 10.0
WL	Chargers	13- 3
Teams	Eagles	11- 5
(7)	Cowboys	11- 5
	Packers	11- 5
	Patriots	10- 6
	Steelers	9- 7
	Seahawks	5-11	avg wins: 10.0
LW	Bengals	10- 6
Teams	Cardinals	10- 6
(7)	Texans	9- 7
	Bears	7- 9
	Bills	6-10
	Raiders	5-11
	Redskins	4-12	avg wins: 7.3
LL	Panthers	8- 8
Teams	Titans	8- 8
(9)	Dolphins	7- 9
	Jaguars	7- 9
	Browns	5-11
	Chiefs	4-12
	Buccaneers	3-13
	Lions	2-14
	Rams	1-15	avg wins: 5.0

Comments:

• I'm somewhat surprised at how well the first two games correlate to overall success. But it's good to see such strong evidence for one of FSPI's basic assumptions (i.e., that you can tell something about how good a team is from just one or two games).

• It seems a little unusual that most teams fall into the 'WW' or 'LL' categories. I would have expected more of a Normal distribution, with most teams in the 'WL' and 'LW' categories.

• As with the previous historical analysis, there is a significant difference between the 'WL' and the 'LW' groups, although unlike the historical data, this year it was the 'WL' teams that did noticeably better.