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Ten thousand 2005s

Posted by Doug on June 6, 2006

Prerequisite reading material:

How often does the best team win?

Ten thousand seasons

Ten thousand seasons again

In the previous posts, I simulated ten thousand generic NFL seasons. In some of those seasons the "Seattle Seahawks" were great. In some they were terrible. In some they played a tough schedule, in others an easy one. In this post, I'll simulate ten thousand 2005 NFL seasons. The Seattle Seahawks will be a very good team in each of them, and they will play an easy schedule in each of them.

Mechanically, the procedures are similar, but philosophically there is a world of difference. The generic seasons had teams whose strengths I knew, so I could say things like "the best team" and "Chicago was not very good." I knew who the best team was and I knew how good Chicago was or wasn't. Exactly. Only because I knew those team strengths could I assign the proper probabilities to each game.

But if I want to simulate the 2005 season, I've got a problem: I don't know the team strengths. Neither do you. We have to guess. The guess I'm going to use is the team's rating from the simple rating system. I'm not going to spend time here making a case that that's the best guess or even necessarily a good guess. If you don't think the simple rating system is an adequate representation of team strength, that's fine. No hard feelings. But you'd better stop reading now, because that's the foundation this post rests on.

For those still with me, I'll make one more disclaimer. If I happen to say something like:

Seattle was the 4th-best team in football.

What I actually mean is:

According to the measurement of team strength that we have agreed upon --- which we acknowledge is imperfect in some obvious and some non-obvious ways --- Seattle appears to be the 4th-best team in football.

I am not trying to quash discussion of the merits of the various ways of estimating team strength and I am well aware of the weaknesses of the one I have chosen. But we've got to pick something and go with it, and the prose just seems to flow a bit better if you allow me to use the above shorthand notation. As you know, I can use all the help I can get with making the prose flow.

Now let's get to it. I'll just throw this summary out and then we'll discuss it.

Rating is the team's rating, which is my guess as to its true strength. Avg Wins is the average number of wins each team had over the course of the 10,000 seasons. Div is the number of division titles each team won. WC is the number of times each team got into the playoffs as a wildcard. PO = Div + WC. It is the number of times each team made the playoffs. SB is the number times each team made it to the Super Bowl and Champ is the number of times they won it.


TM Rating AvgWins Div WC PO SB Champ
=====+=========+========+================+===========
ind | 10.8 | 11.2 | 7128 1572 8700 | 2688 1640
sea | 9.1 | 11.1 | 8936 395 9331 | 3461 1780
car | 5.1 | 10.4 | 6304 1818 8122 | 1681 741
den | 10.8 | 10.4 | 4342 2797 7139 | 1825 1092
pit | 7.8 | 10.3 | 5741 1543 7284 | 1469 778
nyg | 7.5 | 10.1 | 5083 2534 7617 | 1785 817
sdg | 9.9 | 9.9 | 3190 2907 6097 | 1343 797
jax | 4.8 | 9.6 | 2727 2951 5678 | 674 321
kan | 7.0 | 9.4 | 2298 2842 5140 | 737 371
cin | 3.8 | 9.3 | 3015 1974 4989 | 516 242
was | 6.0 | 9.2 | 2986 2765 5751 | 989 416
chi | 1.4 | 9.1 | 5653 793 6446 | 721 256
nwe | 3.1 | 8.7 | 5001 476 5477 | 425 194
tam | -1.0 | 8.5 | 1969 2333 4302 | 315 103
dal | 3.2 | 8.3 | 1552 2249 3801 | 409 166
atl | -1.2 | 8.2 | 1652 2122 3774 | 236 73
mia | -0.8 | 8.0 | 3385 481 3866 | 165 52
rav | -1.8 | 7.4 | 773 829 1602 | 61 22
min | -3.5 | 7.3 | 1864 774 2638 | 113 36
gnb | -3.7 | 7.1 | 1616 755 2371 | 93 29
ram | -5.1 | 6.9 | 528 1013 1541 | 59 10
cle | -4.2 | 6.8 | 471 518 989 | 32 9
crd | -5.0 | 6.7 | 481 884 1365 | 46 9
phi | -2.3 | 6.6 | 379 878 1257 | 61 16
rai | -2.8 | 6.3 | 170 427 597 | 22 9
det | -6.7 | 6.3 | 867 417 1284 | 27 6
buf | -5.8 | 6.2 | 889 179 1068 | 20 7
nyj | -6.4 | 6.0 | 725 136 861 | 18 6
oti | -7.6 | 5.8 | 108 256 364 | 4 2
htx | -10.0 | 5.1 | 37 112 149 | 1 0
nor | -11.1 | 4.9 | 75 139 214 | 4 0
sfo | -11.1 | 4.7 | 55 131 186 | 0 0

Indianapolis averaged 11.2 wins per season in the simulation. They won the AFC South 71.2 percent of the time, they made the playoffs 87% of the time, they made it to the Super Bowl about 27% of the time and won it 16.4% of the time.

If you were to translate this into an English sentence, it would not be: at the beginning of the season, we should have estimated that the Colts had a 16.4% chance of winning the Super Bowl. It would be something more like: knowing what we now know in hindsight about how good these teams were in 2005, if we were to play the season again with those strengths remaining the same, the Colts would have a 16.4% chance of winning the Super Bowl. Alright, that's pretty bad English but I hope you get the point.

The probability of winning the Super Bowl depends two things: the team's strength and their schedule (including the playoff schedule). You can see the effect of both in the table. Denver and Indianapolis were essentially equally strong, but the Colts' chances of winning the Super Bowl were significantly higher. And Seattle's were even higher, despite being a weaker team. Carolina had a title chance that was disproportionately high (compared to their true strength) and San Diego's was disproportionally low. We'll revisist them in a moment.

Also note that the spread on average wins --- from Indy's 10.8 to Houston's 4.7 --- is much smaller than the spread on actual wins in the 2005 season. This makes sense. I think it's safe to say that there is almost never an NFL team that is morally a 14-2 team or a 2-14 team. There are, though, probably three or four teams each year --- maybe more --- that are capable of going 14-2 if things break right for them, and there are another few that might slip to 2-14 if things don't. And the result is that we see 14-2 teams and 2-14 with some regularity. This idea might strike some people as controversial, but it's really no different from pointing out that no basketball player truly is a 50-point-per-game player even though certain players do score 50 from time to time.

OK, time to play god. Let's move the Chargers to the NFC South and the Panthers to the AFC West and see what happens.


TM Rating AvgWins Div WC PO SB Champ
=====+=========+========+================+===========
sdg | 9.9 | 11.7 | 8209 1158 9367 | 3344 1790
clt | 10.8 | 11.3 | 7255 1615 8870 | 2881 1610
sea | 9.1 | 11.1 | 8921 398 9319 | 2879 1520
den | 10.8 | 10.6 | 5370 2328 7698 | 2134 1196
pit | 7.8 | 10.4 | 5795 1684 7479 | 1563 787
nyg | 7.5 | 10.1 | 5063 2508 7571 | 1478 727
jax | 4.8 | 9.7 | 2592 3360 5952 | 731 317
kan | 7.0 | 9.6 | 2980 2784 5764 | 902 441
was | 6.0 | 9.3 | 3015 2879 5894 | 827 366
cin | 3.8 | 9.3 | 2979 2222 5201 | 570 256
chi | 1.4 | 9.0 | 5504 754 6258 | 522 184
nwe | 3.1 | 8.7 | 4984 487 5471 | 476 195
car | 5.1 | 8.5 | 1385 2076 3461 | 388 179
tam | -1.0 | 8.3 | 979 2862 3841 | 173 63
dal | 3.2 | 8.3 | 1530 2287 3817 | 306 138
atl | -1.2 | 8.0 | 782 2516 3298 | 147 38
mia | -0.8 | 8.0 | 3298 551 3849 | 180 56
rav | -1.8 | 7.4 | 778 960 1738 | 62 23
min | -3.5 | 7.3 | 1933 661 2594 | 88 19
gnb | -3.7 | 7.0 | 1681 634 2315 | 86 22
ram | -5.1 | 6.9 | 559 1011 1570 | 36 6
cle | -4.2 | 6.8 | 448 593 1041 | 25 6
phi | -2.3 | 6.7 | 392 924 1316 | 49 19
crd | -5.0 | 6.6 | 458 793 1251 | 37 12
rai | -2.8 | 6.5 | 265 524 789 | 33 10
det | -6.7 | 6.3 | 882 369 1251 | 28 6
buf | -5.8 | 6.2 | 935 222 1157 | 32 10
nyj | -6.4 | 6.0 | 783 152 935 | 18 2
oti | -7.6 | 5.9 | 113 315 428 | 4 1
htx | -10.0 | 5.1 | 40 127 167 | 1 1
nor | -11.1 | 4.8 | 30 133 163 | 0 0
sfo | -11.1 | 4.7 | 62 113 175 | 0 0

Interesting.

This entry was posted on Tuesday, June 6th, 2006 at 4:05 am and is filed under Statgeekery. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.