29 Comments
Jan 25Liked by Neil Paine

Your work is really good, especially considering that 538 is no longer around. Do you have any links to ELO ratings from previous weeks, just as a way of seeing how teams have improved or regressed? I know that on 538 they had it so that you could look at rankings from previous weeks/years?

Expand full comment
author

The whole Elo archive is here: https://github.com/Neil-Paine-1/NFL-elo-ratings

Expand full comment
Dec 28, 2023Liked by Neil Paine

How are you deriving your PPG Ratings for Elo and the Andy Dolphin Ratings? Thanks (Sorry if I overlooked that somewhere).

Expand full comment
author

Elo is easy, you just take the difference in rating from league average and divide by 25 (as per our handy explainer: https://fivethirtyeight.com/features/introducing-nfl-elo-ratings/) ... For Dolphin, I had to rescale his "predictive" values from here (http://www.dolphinsim.com/ratings/nfl/) into point ratings by converting them to a common scale with the other point-based ratings using Z-scores.

Expand full comment

ok cool, I do essentially the same to standardize DVOA against FPI, GPF, etc. I wonder why you use the /25 math to scale Elo though? By the same logic you use for the dolphin predictive values, if you scaled Elo against the average distribution of various PPG ratings you get largely different values. for instance, Ari adjusts to -5.9 (using the /25 math) vs roughly -7.6 when scaled against other power ratings scales. Baltimore (my team) would be 8.9 vs 11.4. Could you explain your rationale? Thanks.

Expand full comment

Late comment, but dividing by 25, means that team's that are favored by 400/25 = 16, should win 10/11 times (91%). It makes the elo scale match up with how Vegas does point spreads.

Typically in Vegas odds you'd see that,

+2 = 55%

+3 = 60%

+4 = 65%

+6 = 70%

+7 = 75%

+9 = 80%

+12.5 = 85%

+14 = 90%

The reason the elo ratings are more "compact" is because 1. they are predictive rather than explanatory 2. probably have less information about injuries, starting QB, etc. so are necessarily more conservative estimates that are "regressed to the mean"

Expand full comment
author

Honestly it was just out of convenience... That "divide by 25" rule of thumb is what I've always used to convert between NFL Elo and pointspreads. I haven't really looked into how accurate it is in quite a while, so it's possible it needs updating.

Expand full comment
Dec 21, 2023Liked by Neil Paine

I make my picks based on your composite rankings - any chance for an update this week?

Expand full comment
author

Yep! Thanks for the reminder.

Expand full comment
Dec 21, 2023Liked by Neil Paine

Fantastic! Thanks for all your work!

Expand full comment
Dec 12, 2023Liked by Neil Paine

Do you have the playoff rules coded so you could add a column for the odds to make the playoffs?

Expand full comment
author

Sadly, I did not have time to do that before the season started. (The tiebreakers are always a pain in the behind to program!) For that, I think the NY Times' Playoff Picture interactive is great: https://www.nytimes.com/interactive/2023/upshot/nfl-playoff-picture.html

In fact, they have that whole thing set up as well or better than we had back at 538. They even use Elo as part of the ratings: https://www.nytimes.com/2023/10/13/upshot/nfl-playoff-odds-simulator.html They say it's blended with betting market ratings, so I have to assume it's mixed with something like this: https://stats.inpredictable.com/rankings/nfl.php And honestly that's exactly how I would do it.

Expand full comment

How do u calculate the win probabilities?

Expand full comment
Oct 24, 2023Liked by Neil Paine

Question, since QBs aren't factored in should we be factoring in the difference based on the lines provided?

Expand full comment
author

Yes, I would mentally account for QB absences on top of these lines using something like this: https://ftw.usatoday.com/lists/nfl-quarterbacks-against-the-spread-worth-ranked-backups

Expand full comment
Oct 25, 2023Liked by Neil Paine

Wow bro, thank you so much! This is super helpful!

Expand full comment
Oct 15, 2023Liked by Neil Paine

I lived on 538 last season looking at all these data points.

I am so glad I found them again! Thanks for the time and effort. My time will be spent here a lot!

Expand full comment

Wow, big swing on expected margin for the Jets-Broncos game based on the Bears Thursday night win.

Expand full comment
author

That shouldn’t have changed (other results don’t affect Elo until a team plays), lemme see what’s going on there.

Expand full comment
author

OK, I checked and it was saying DEN -1.5 before today's update too. Maybe you were looking at a different game?

Expand full comment
Oct 6, 2023Liked by Neil Paine

Yep, my mistake.

Expand full comment
author

No worries! Thanks for reading

Expand full comment
Oct 6, 2023Liked by Neil Paine

Neil, thank you for keeping these going!

Expand full comment
author

My pleasure. Someday, somewhere I'll revive the QB adjustments too. Just too much else going on and not enough time to get it up and running by the start of the season.

Expand full comment
Sep 27, 2023Liked by Neil Paine

Does win probability mean win against the spread or just an out right win?

Expand full comment
author

Just a win straight-up.

Expand full comment
Sep 22, 2023Liked by Neil Paine

Neil, you have the Raiders-Steelers game as OAK -.5. The Raiders are in Las Vegas! Should be SIN CITY -.5.

Expand full comment
author

Oh man, I need to update my team IDs! Lol. Thanks for the catch!

Expand full comment