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AFL versus NFL: the power ratings

Posted by Jason Lisk on December 22, 2009

I could have handled the conclusions one of two ways. The first would have been to present all my conclusions and then have a chart of all the AFL and NFL teams from the decade with their ratings. The second way is to present the results first, and then follow up with how I got there. I opted for the second way, as I didn't want the results and actual team ratings to be a footnote at the end of the series. These ratings, after all, were the reason I started on this path in the first place. I wanted to see how an NFL team compared in 1964 to an AFL team, how the champions of each league compared, and so forth.

I don't claim that these numbers are completely accurate or infallible. There is simply year to year variation across leagues and teams that we can't measure accurately. How do the 2007 Colts compare to the 2009 Colts? We don't know, because they didn't play in the exact same situation, and that's with a lot more direct information to draw upon than what we have when comparing the AFL and NFL. We do have numbers upon which we can make reasonable estimates though. Similarly, these numbers represent my best available guess of how teams compared during the decade of the 1960's. If you've been following along and read the entire series up until now, you probably have some idea how I got there, but I'll explain in the final post how I settled on the best guesses that I did.

Let's get to the ratings. As I noted in the Super Bowl, part two post, these ratings are similar to the Simple Rating System method, with the following tweaks:

1) My ratings have a soft cap at 24 points. Any margins beyond 24 points in a specific game are halved. So a 38 point victory would actually count as a 31 point spread in the ratings. This is to reduce the effect of single blowout games, while still rewarding teams that consistently win comfortably. A team with a 40 point win followed by a 10 point loss will have a lower rating than a team with two 15 point wins (assuming equal opponent strength).

2) My ratings exclude end of regular season games involving a team that has already clinched its division. It seems pretty clear to me that teams performed worse in the 1960's when they had nothing to play for. There was no seeding in the playoffs at that time, so once a team clinched a division title, the motivation was simply to be ready for the playoff game. Thus, many of the playoff teams have higher ratings in my system than they do considering all the results.

3) My ratings include the playoff games within the same league (but not the Super Bowl games). The SRS figures on the team pages are regular season only.

4) As a result of 2 and 3, above, my ratings also include a home field advantage adjustment for teams that played an uneven number of home or road games.

Unlike that post, though, these ratings also include a league adjustment. That adjustment was made based on my estimate of the differences between the leagues in a given year. If you combine the AFL adjustment (a negative number) with the NFL adjustment (a positive number) you get my overall estimate of the differences. The reason these numbers are not equal is because the leagues had a different number of teams. The overall effect should be that the average team (AFL and NFL combined) should equal roughly zero in the rating system. Thus, the NFL had more above average teams early in the decade when the AFL would have rated lower. I was tempted to make an adjustment to the early part of the decade, because I do believe that the initial effect of expansion had an impact on quality across the board, until the numbers and influx of the African-American increase and the baby boomer increase caught up. However, I didn't have a good idea of how to fairly do that, so for now, these numbers are merely adjusted within seasons (to compare the AFL in 1964 to the NFL in 1964), and not across seasons for both leagues. Thus, an average team in 1960 (among the 21 teams) is viewed equal to an average team in 1968 (among 26 teams).

This table is sortable. Currently, it is sorted by year (ascending), league, and power rating (descending). You should be able to sort it by team, league, rating for the decade, etc. The team abbreviations are by city, so the Cardinals are STL, the Patriots are BOS, and the Chiefs are KAN, since they played the majority of games there, instead of Dallas. Enjoy.

Year league team rating margin schedule lg adj adj rating
1960 AFL kan 6.5 7.5 -1.0 -8.0 -1.5
1960 AFL hou 5.7 6.1 -0.4 -8.0 -2.3
1960 AFL sdg 2.5 2.4 0.1 -8.0 -5.5
1960 AFL buf -0.8 -0.9 0.1 -8.0 -8.8
1960 AFL nyj -1.1 -1.0 -0.1 -8.0 -9.1
1960 AFL bos -3.8 -3.9 0.1 -8.0 -11.8
1960 AFL oak -4.6 -5.3 0.6 -8.0 -12.6
1960 AFL den -4.8 -5.4 0.6 -8.0 -12.8
1960 NFL cle 9.6 10.6 -1.0 5.0 14.6
1960 NFL phi 7.3 5.9 1.5 5.0 12.3
1960 NFL gnb 7.1 8.7 -1.6 5.0 12.1
1960 NFL crd 4.1 4.0 0.1 5.0 9.1
1960 NFL nyg 1.6 0.8 0.8 5.0 6.6
1960 NFL bal 1.5 3.5 -2.0 5.0 6.5
1960 NFL det 1.2 1.8 -0.6 5.0 6.2
1960 NFL sfo -0.5 0.4 -0.9 5.0 4.5
1960 NFL pit -1.6 -3.0 1.4 5.0 3.4
1960 NFL ram -2.9 -2.7 -0.2 5.0 2.1
1960 NFL chi -6.1 -6.9 0.8 5.0 -1.1
1960 NFL was -8.0 -10.1 2.1 5.0 -3.0
1960 NFL dal -13.2 -14.3 1.1 5.0 -8.2
1961 AFL hou 14.8 15.9 -1.2 -7.0 7.8
1961 AFL sdg 12.3 13.1 -0.8 -7.0 5.3
1961 AFL bos 2.5 3.9 -1.4 -7.0 -4.5
1961 AFL kan -0.7 -0.8 0.1 -7.0 -7.7
1961 AFL buf -2.8 -2.3 -0.6 -7.0 -9.8
1961 AFL nyj -4.8 -5.4 0.7 -7.0 -11.8
1961 AFL den -9.9 -11.3 1.4 -7.0 -16.9
1961 AFL oak -11.6 -13.2 1.6 -7.0 -18.6
1961 NFL gnb 15.0 13.0 2.0 4.0 19.0
1961 NFL nyg 5.3 6.9 -1.6 4.0 9.3
1961 NFL sfo 4.6 4.2 0.4 4.0 8.6
1961 NFL chi 4.2 3.8 0.4 4.0 8.2
1961 NFL det 4.0 1.2 2.8 4.0 8.0
1961 NFL bal 1.9 -0.1 1.9 4.0 5.9
1961 NFL cle 1.7 3.6 -1.9 4.0 5.7
1961 NFL phi 1.3 3.9 -2.6 4.0 5.3
1961 NFL crd -1.5 0.9 -2.4 4.0 2.5
1961 NFL ram -1.5 -4.4 2.9 4.0 2.5
1961 NFL pit -2.3 0.2 -2.5 4.0 1.7
1961 NFL min -6.0 -8.6 2.5 4.0 -2.0
1961 NFL dal -12.1 -10.0 -2.2 4.0 -8.1
1961 NFL was -14.9 -14.5 -0.4 4.0 -10.9
1962 AFL kan 10.4 11.1 -0.7 -5.4 5.0
1962 AFL hou 6.4 6.5 -0.2 -5.4 1.0
1962 AFL bos 3.1 3.4 -0.4 -5.4 -2.3
1962 AFL buf 2.3 2.6 -0.3 -5.4 -3.1
1962 AFL den 0.7 1.5 -0.9 -5.4 -4.7
1962 AFL sdg -5.3 -5.3 0.0 -5.4 -10.7
1962 AFL nyj -8.0 -9.2 1.2 -5.4 -13.4
1962 AFL oak -9.3 -10.6 1.4 -5.4 -14.7
1962 NFL gnb 17.0 16.3 0.7 3.1 20.1
1962 NFL det 11.5 9.4 2.1 3.1 14.6
1962 NFL chi 5.5 2.4 3.1 3.1 8.6
1962 NFL nyg 5.2 7.0 -1.9 3.1 8.3
1962 NFL bal 4.0 1.4 2.6 3.1 7.1
1962 NFL sfo -0.3 -3.5 3.2 3.1 2.8
1962 NFL cle -1.3 2.6 -4.0 3.1 1.8
1962 NFL dal -3.2 0.7 -3.9 3.1 -0.1
1962 NFL ram -4.3 -7.9 3.6 3.1 -1.2
1962 NFL pit -5.7 -3.0 -2.6 3.1 -2.6
1962 NFL phi -6.6 -4.5 -2.1 3.1 -3.5
1962 NFL min -6.9 -10.8 3.9 3.1 -3.8
1962 NFL crd -7.0 -5.5 -1.6 3.1 -3.9
1962 NFL was -7.6 -4.9 -2.7 3.1 -4.5
1963 AFL sdg 9.3 10.5 -1.1 -5.1 4.2
1963 AFL oak 5.1 6.0 -0.9 -5.1 0.0
1963 AFL bos 3.7 3.7 0.0 -5.1 -1.4
1963 AFL kan 3.2 3.8 -0.6 -5.1 -1.9
1963 AFL buf -0.4 -0.6 0.2 -5.1 -5.5
1963 AFL hou -3.7 -4.1 0.4 -5.1 -8.8
1963 AFL nyj -7.7 -8.6 1.0 -5.1 -12.8
1963 AFL den -9.2 -10.3 1.2 -5.1 -14.3
1963 NFL gnb 10.6 11.5 -0.8 2.9 13.5
1963 NFL chi 9.4 10.2 -0.8 2.9 12.3
1963 NFL nyg 9.1 10.7 -1.6 2.9 12.0
1963 NFL cle 4.5 5.9 -1.4 2.9 7.4
1963 NFL det 3.5 3.8 -0.3 2.9 6.4
1963 NFL crd 3.0 3.5 -0.5 2.9 5.9
1963 NFL pit 2.3 1.7 0.6 2.9 5.2
1963 NFL bal 2.1 2.1 0.1 2.9 5.0
1963 NFL min -4.5 -5.0 0.6 2.9 -1.6
1963 NFL dal -5.2 -5.0 -0.2 2.9 -2.3
1963 NFL was -7.9 -8.2 0.2 2.9 -5.0
1963 NFL ram -7.9 -9.1 1.2 2.9 -5.0
1963 NFL phi -8.4 -9.5 1.1 2.9 -5.5
1963 NFL sfo -10.5 -12.7 2.1 2.9 -7.6
1964 AFL buf 9.9 11.0 -1.0 -4.9 5.0
1964 AFL sdg 5.5 5.4 0.1 -4.9 0.6
1964 AFL bos 4.1 4.8 -0.7 -4.9 -0.8
1964 AFL kan 0.2 0.8 -0.5 -4.9 -4.7
1964 AFL nyj -1.9 -2.2 0.2 -4.9 -6.8
1964 AFL hou -2.6 -2.9 0.3 -4.9 -7.5
1964 AFL oak -3.3 -3.3 0.0 -4.9 -8.2
1964 AFL den -11.8 -13.4 1.6 -4.9 -16.7
1964 NFL bal 13.1 11.7 1.3 2.8 15.9
1964 NFL gnb 8.2 6.9 1.4 2.8 11.0
1964 NFL cle 7.4 9.5 -2.1 2.8 10.2
1964 NFL min 4.8 4.4 0.4 2.8 7.6
1964 NFL det 1.5 0.5 1.0 2.8 4.3
1964 NFL crd -0.1 1.9 -2.1 2.8 2.7
1964 NFL ram -0.6 -6.9 6.3 2.8 2.2
1964 NFL was -1.2 2.0 -3.1 2.8 1.6
1964 NFL phi -2.9 -0.2 -2.8 2.8 -0.1
1964 NFL sfo -3.8 -5.7 1.9 2.8 -1.0
1964 NFL dal -4.5 -2.7 -1.9 2.8 -1.7
1964 NFL chi -4.7 -7.3 2.6 2.8 -1.9
1964 NFL pit -5.9 -4.2 -1.7 2.8 -3.1
1964 NFL nyg -11.2 -10.5 -0.7 2.8 -8.4
1965 AFL buf 7.8 8.0 -0.2 -4.7 3.1
1965 AFL sdg 5.2 5.3 -0.1 -4.7 0.5
1965 AFL oak 3.6 4.1 -0.5 -4.7 -1.1
1965 AFL kan 2.2 3.2 -0.9 -4.7 -2.5
1965 AFL nyj -1.8 -1.5 -0.3 -4.7 -6.5
1965 AFL bos -3.7 -4.3 0.6 -4.7 -8.4
1965 AFL den -5.2 -6.0 0.8 -4.7 -9.9
1965 AFL hou -7.8 -8.5 0.6 -4.7 -12.5
1965 NFL chi 12.9 9.0 3.8 2.7 15.6
1965 NFL bal 11.5 6.9 4.6 2.7 14.2
1965 NFL gnb 10.2 6.1 4.1 2.7 12.9
1965 NFL sfo 6.4 1.9 4.5 2.7 9.1
1965 NFL min 4.1 -1.4 5.5 2.7 6.8
1965 NFL det 2.9 -2.5 5.4 2.7 5.6
1965 NFL ram -0.1 -6.9 6.8 2.7 2.6
1965 NFL cle -0.6 4.9 -5.5 2.7 2.1
1965 NFL dal -2.2 3.1 -5.3 2.7 0.5
1965 NFL phi -5.1 0.0 -5.1 2.7 -2.4
1965 NFL crd -6.3 -0.9 -5.4 2.7 -3.6
1965 NFL was -7.8 -2.8 -5.0 2.7 -5.1
1965 NFL nyg -8.9 -4.5 -4.4 2.7 -6.2
1965 NFL pit -16.3 -13.0 -3.3 2.7 -13.6
1966 AFL kan 12.4 13.0 -0.6 -4.3 8.1
1966 AFL buf 5.3 4.6 0.7 -4.3 1.0
1966 AFL sdg 4.1 4.5 -0.4 -4.3 -0.2
1966 AFL bos 2.6 2.3 0.3 -4.3 -1.7
1966 AFL oak 1.4 2.2 -0.8 -4.3 -2.9
1966 AFL nyj 0.1 0.2 -0.1 -4.3 -4.2
1966 AFL hou -5.0 -4.5 -0.5 -4.3 -9.3
1966 AFL mia -10.1 -10.2 0.1 -4.3 -14.4
1966 AFL den -10.7 -11.8 1.2 -4.3 -15.0
1966 NFL gnb 12.6 11.5 1.1 2.6 15.2
1966 NFL dal 8.8 11.0 -2.2 2.6 11.4
1966 NFL cle 7.3 9.6 -2.3 2.6 9.9
1966 NFL bal 6.9 5.9 1.0 2.6 9.5
1966 NFL ram 5.1 5.7 -0.6 2.6 7.7
1966 NFL min 1.5 -1.0 2.5 2.6 4.1
1966 NFL sfo 1.1 -0.8 1.8 2.6 3.7
1966 NFL chi -0.6 -2.6 2.0 2.6 2.0
1966 NFL phi -1.8 0.0 -1.8 2.6 0.8
1966 NFL was -1.8 -0.4 -1.4 2.6 0.8
1966 NFL crd -2.1 -0.2 -1.9 2.6 0.5
1966 NFL pit -3.7 -1.7 -2.0 2.6 -1.1
1966 NFL det -5.0 -7.6 2.5 2.6 -2.4
1966 NFL atl -13.6 -14.5 1.0 2.6 -11.0
1966 NFL nyg -14.9 -15.3 0.4 2.6 -12.3
1967 AFL oak 15.7 17.0 -1.3 -3.7 12.0
1967 AFL kan 9.3 9.5 -0.3 -3.7 5.6
1967 AFL nyj 2.0 3.5 -1.5 -3.7 -1.7
1967 AFL hou 1.8 3.0 -1.3 -3.7 -1.9
1967 AFL sdg 1.2 1.0 0.3 -3.7 -2.5
1967 AFL buf -4.8 -3.7 -1.0 -3.7 -8.5
1967 AFL bos -6.6 -7.6 1.0 -3.7 -10.3
1967 AFL den -7.0 -9.5 2.5 -3.7 -10.7
1967 AFL mia -11.3 -12.5 1.2 -3.7 -15.0
1967 NFL ram 12.0 12.6 -0.6 2.1 14.1
1967 NFL bal 11.8 12.4 -0.6 2.1 13.9
1967 NFL gnb 11.3 10.2 1.1 2.1 13.4
1967 NFL dal 4.5 5.5 -1.1 2.1 6.6
1967 NFL chi 2.8 1.4 1.4 2.1 4.9
1967 NFL det 1.4 -0.2 1.6 2.1 3.5
1967 NFL cle 1.0 1.7 -0.7 2.1 3.1
1967 NFL nyg -1.9 -1.0 -0.9 2.1 0.2
1967 NFL was -2.0 -0.4 -1.6 2.1 0.1
1967 NFL min -2.4 -3.8 1.4 2.1 -0.3
1967 NFL crd -2.7 -1.9 -0.8 2.1 -0.6
1967 NFL sfo -3.1 -4.5 1.4 2.1 -1.0
1967 NFL phi -4.4 -2.5 -1.9 2.1 -2.3
1967 NFL pit -5.3 -3.9 -1.4 2.1 -3.2
1967 NFL nor -10.3 -9.9 -0.4 2.1 -8.2
1967 NFL atl -13.1 -16.1 3.0 2.1 -11.0
1968 AFL oak 13.7 14.1 -0.5 -2.2 11.5
1968 AFL kan 11.0 10.5 0.4 -2.2 8.8
1968 AFL nyj 7.5 7.8 -0.3 -2.2 5.3
1968 AFL sdg 6.2 5.7 0.5 -2.2 4.0
1968 AFL hou 2.8 3.9 -1.1 -2.2 0.6
1968 AFL mia -4.9 -3.1 -1.9 -2.2 -7.1
1968 AFL cin -6.4 -7.3 1.0 -2.2 -8.6
1968 AFL den -8.2 -9.4 1.2 -2.2 -10.4
1968 AFL buf -9.9 -10.9 0.9 -2.2 -12.1
1968 AFL bos -11.7 -11.3 -0.4 -2.2 -13.9
1968 NFL bal 17.8 18.1 -0.3 1.4 19.2
1968 NFL dal 11.4 13.9 -2.5 1.4 12.8
1968 NFL ram 8.3 8.7 -0.4 1.4 9.7
1968 NFL cle 6.6 6.4 0.3 1.4 8.0
1968 NFL gnb 3.4 3.7 -0.3 1.4 4.8
1968 NFL min 2.9 1.9 1.0 1.4 4.3
1968 NFL sfo 1.6 -0.3 1.9 1.4 3.0
1968 NFL crd 0.6 2.1 -1.5 1.4 2.0
1968 NFL nyg -1.7 -0.3 -1.5 1.4 -0.3
1968 NFL det -1.7 -2.2 0.5 1.4 -0.3
1968 NFL chi -4.1 -4.9 0.8 1.4 -2.7
1968 NFL nor -6.7 -5.7 -1.1 1.4 -5.3
1968 NFL was -8.3 -7.5 -0.8 1.4 -6.9
1968 NFL pit -9.7 -9.5 -0.2 1.4 -8.3
1968 NFL phi -10.3 -9.8 -0.5 1.4 -8.9
1968 NFL atl -10.4 -14.0 3.6 1.4 -9.0
1969 AFL kan 12.4 13.0 -0.6 -1.9 10.5
1969 AFL oak 9.5 9.7 -0.2 -1.9 7.6
1969 AFL nyj 2.9 3.9 -1.0 -1.9 1.0
1969 AFL sdg 1.1 0.7 0.4 -1.9 -0.8
1969 AFL den -1.9 -2.9 0.9 -1.9 -3.8
1969 AFL hou -2.6 -2.2 -0.4 -1.9 -4.5
1969 AFL bos -3.8 -3.0 -0.8 -1.9 -5.7
1969 AFL cin -3.9 -5.5 1.6 -1.9 -5.8
1969 AFL mia -5.8 -5.5 -0.3 -1.9 -7.7
1969 AFL buf -7.7 -8.0 0.4 -1.9 -9.6
1969 NFL min 17.8 17.2 0.7 1.2 19.0
1969 NFL ram 10.4 9.6 0.8 1.2 11.6
1969 NFL gnb 6.2 4.3 1.9 1.2 7.4
1969 NFL det 5.0 3.5 1.6 1.2 6.2
1969 NFL dal 3.9 7.0 -3.0 1.2 5.1
1969 NFL cle 3.5 4.4 -0.9 1.2 4.7
1969 NFL bal 3.2 1.7 1.5 1.2 4.4
1969 NFL atl 1.6 0.3 1.4 1.2 2.8
1969 NFL sfo -1.6 -3.4 1.9 1.2 -0.4
1969 NFL was -3.1 -0.6 -2.5 1.2 -1.9
1969 NFL chi -5.7 -9.4 3.7 1.2 -4.5
1969 NFL nyg -6.1 -4.3 -1.9 1.2 -4.9
1969 NFL crd -6.8 -5.1 -1.7 1.2 -5.6
1969 NFL nor -7.3 -5.9 -1.4 1.2 -6.1
1969 NFL phi -7.9 -6.6 -1.3 1.2 -6.7
1969 NFL pit -12.8 -12.3 -0.5 1.2 -11.6

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