Game Probabilities Week 14

Win probabilities for week 14 NFL games are listed below. The probabilities are based on an efficiency win model explained here and here with some modifications. The model considers offensive and defensive efficiency stats including running, passing, sacks, turnover rates, and penalty rates. Team stats are adjusted for previous opponent strength.

Pwin	GAME	Pwin
0.09	OAK at SD	0.91
0.54	WAS at BAL	0.46
0.19	JAX at CHI	0.81
0.87	MIN at DET	0.13
0.31	HOU at GB	0.69
0.10	CIN at IND	0.90
0.53	ATL at NO	0.47
0.39	PHI at NYG	0.61
0.09	CLE at TEN	0.91
0.62	MIA at BUF	0.38
0.16	KC at DEN	0.84
0.65	NYJ at SF	0.35
0.04	STL at ARI	0.96
0.29	DAL at PIT	0.71
0.69	NE at SEA	0.31
0.27	TB at CAR	0.73

Change extra points?

Reader Eddy Elfenbein makes a great point about extra points. I also like the idea of narrowing the field goal posts, something Bill Cowher advocated last Sunday. It would not only make extra points less certain, it would make fourth down conversion attempts more common and make overtime less susceptible to the 'lose the coin toss, never touch the ball' phenomenon.

Ideas like these really aren't that revolutionary. They would just be returning the game to its 'natural' balance. Kickers have become so accurate in recent decades that it has warped the game from its original intent. But NFL football has certainly evolved in many ways, and its unparalleled success makes tinkering with it a tough sell.

Extra points have become so automatic, I don't even pay attention. They're just going to be surrounded by commercials featuring that stiff Sprint CEO and the Bud Light drinkability girl in the green jersey. The only reason to watch them is when there is a possibility of a challenge on the touchdown.

Kicking field goals is such a peculiar and specialized thing. It has almost nothing to do with the rest of the sport but can be so decisive. It would be like getting extra runs in baseball by lacing up some skates and slapping a shoot-out shot after every home run.

Week 13 Efficiency Rankings

The ratings are listed below in terms of generic win probability. The GWP is the probability a team would beat the league average team at a neutral site. Each team's opponent's average GWP is also listed, which can be considered to-date strength of schedule, and all ratings include adjustments for opponent strength.

Offensive rank (ORANK) is offensive generic win probability which is based on each team's offensive efficiency stats only. In other words, it's the team's GWP assuming it had a league-average defense. DRANK is is a team's generic win probability rank assuming it had a league-average offense.

GWP is based on a logistic regression model applied to current team stats. The model includes offensive and defensive passing and running efficiency, offensive turnover rates, and team penalty rates. A full explanation of the methodology can be found here. This year, however, I've made one important change based on research that strongly indicates that defensive interception rates are highly random and not consistent throughout the year. Accordingly, I've removed them from the model and updated the weights of the remaining stats.

RANK	TEAM	LAST WK	GWP	Opp GWP	O RANK	D RANK
1	ATL	4	0.79	0.54	1	19
2	NYG	6	0.76	0.49	2	8
3	CAR	3	0.75	0.54	10	6
4	PHI	7	0.74	0.52	9	5
5	SD	1	0.73	0.56	3	15
6	PIT	8	0.73	0.50	21	1
7	WAS	2	0.73	0.52	7	9
8	TEN	11	0.70	0.41	13	2
9	NO	8	0.70	0.55	4	17
10	MIA	9	0.66	0.46	5	23
11	ARI	10	0.65	0.55	6	18
12	TB	13	0.63	0.52	20	4
13	DAL	14	0.62	0.48	12	10
14	BAL	18	0.61	0.48	18	3
15	IND	15	0.58	0.52	11	14
16	CHI	12	0.58	0.50	19	11
17	DEN	19	0.53	0.49	8	26
18	GB	20	0.52	0.55	14	13
19	NYJ	16	0.51	0.46	25	16
20	NE	17	0.50	0.50	17	24
21	MIN	21	0.50	0.51	24	7
22	BUF	22	0.44	0.40	26	21
23	HOU	23	0.42	0.46	15	29
24	JAX	24	0.32	0.47	16	25
25	OAK	26	0.29	0.56	30	12
26	SEA	25	0.28	0.47	29	20
27	CLE	28	0.26	0.55	23	28
28	KC	29	0.24	0.54	22	30
29	SF	27	0.23	0.53	27	27
30	CIN	30	0.19	0.59	32	22
31	STL	31	0.11	0.56	28	31
32	DET	32	0.09	0.57	31	32

To-date efficiency stats below. As always, click on the headers to sort.

TEAM	OPASS	ORUN	OINTRATE	OFUMRATE	DPASS	DRUN	DINTRATE	PENRATE
ARI	7.3	3.3	0.023	0.026	6.4	3.8	0.026	0.38
ATL	7.4	4.3	0.018	0.011	6.1	4.8	0.022	0.30
BAL	6.0	3.8	0.027	0.024	5.2	3.5	0.052	0.43
BUF	6.5	4.0	0.030	0.030	6.1	4.1	0.018	0.30
CAR	6.7	4.4	0.027	0.018	5.5	4.1	0.024	0.36
CHI	5.6	4.0	0.023	0.017	5.9	3.4	0.039	0.34
CIN	4.1	3.4	0.029	0.030	6.5	4.0	0.021	0.30
CLE	5.2	4.1	0.029	0.023	7.1	4.4	0.049	0.32
DAL	7.1	4.3	0.035	0.030	5.5	4.0	0.015	0.48
DEN	7.3	4.5	0.029	0.021	6.9	4.9	0.013	0.37
DET	5.1	3.8	0.039	0.038	7.7	5.1	0.006	0.39
GB	6.3	4.0	0.024	0.024	5.7	4.8	0.045	0.51
HOU	7.1	4.4	0.045	0.026	6.9	4.5	0.029	0.29
IND	6.3	3.5	0.027	0.009	6.0	4.2	0.031	0.33
JAX	5.8	4.1	0.023	0.018	6.8	4.3	0.032	0.45
KC	5.2	4.8	0.030	0.023	7.4	5.0	0.027	0.33
MIA	7.1	4.2	0.016	0.018	6.6	3.9	0.028	0.36
MIN	5.7	4.4	0.040	0.021	6.1	3.2	0.027	0.40
NE	5.9	4.3	0.024	0.019	6.7	4.1	0.034	0.26
NO	7.9	3.6	0.032	0.023	6.3	4.2	0.025	0.40
NYG	6.5	4.9	0.022	0.017	5.4	3.9	0.040	0.46
NYJ	6.1	4.7	0.038	0.027	6.3	3.6	0.023	0.27
OAK	4.9	4.3	0.019	0.037	6.2	4.6	0.037	0.45
PHI	6.3	4.1	0.028	0.015	5.3	3.4	0.030	0.35
PIT	6.0	3.7	0.033	0.020	4.3	3.1	0.031	0.45
SD	7.5	3.9	0.028	0.017	6.4	4.0	0.015	0.35
SF	6.1	4.0	0.039	0.046	6.4	3.8	0.023	0.43
SEA	4.7	4.3	0.037	0.016	7.1	4.1	0.014	0.28
STL	5.0	3.9	0.045	0.024	7.5	4.8	0.018	0.42
TB	5.9	4.1	0.021	0.022	5.5	3.8	0.045	0.41
TEN	6.2	4.2	0.017	0.018	4.9	3.8	0.041	0.39
WAS	5.8	4.7	0.010	0.017	5.7	3.8	0.029	0.34
Avg	6.2	4.1	0.028	0.023	6.2	4.1	0.028	0.37

4th Down Trend?

As most regular readers know, I'm a big proponent of going for it on 4th down far more often than is currently practiced in the NFL. There is good research on when teams should go for it on 4th down, but what about the "currently practiced in the NFL" part? How often do offenses roll the dice? And are teams going for it more frequently?

This two-year-old article by Len Pasquarelli of ESPN.com says that as of late 2006, the trend in the NFL was that offenses were going for it on 4th down more often. I like much of what the article has to say--that going for it on 4th down isn't just for desperate situations and that teams with leads should sometimes go for it.

But in 2006, there was no trend. Pasquarelli's misguided observation was just the product of a small sample size and failing to account for the varying amount of 4th down opportunities there were in each year. Here are the 4th down conversion attempt numbers since 2002 accounting for 4th down opportunities, including projected(*) numbers though 11 games for 2008.

Year	4th Downs	Conv. Attempts	Rate (%)	Conversions	Success (%)
2002	4205	497	12	252	51
2003	4305	501	12	232	46
2004	4185	454	11	219	48
2005	4248	465	11	223	48
2006	4218	473	11	239	51
2007	4152	533	13	261	49
2008*	4096	468	17	252	54

If you just looked at 2004 through 2006, yes, you'd see an increase in absolute numbers of 4th down attempts. But as a percentage of 4th down opportunities, 2006 marked the end of a small downward trend.

Since Pasquarelli's article however, we've seen a remarkable increase in 4th down attempts. 2007 marked the first increase since at least 2002 with a 13% rate. So far 2008 has shown an even larger increase with a 17% rate. The season's not over yet, and two seasons does not a make trend. But something could be changing.