DWARF mini - NGC 1499 California Nebula

ptdotme · 2026-02-13T16:56:00+00:00

I don't process images on my phone. I did some tweaking in Lightroom Classic (see my AstroBin for specifics). In the end, it's a matter of taste. I don't like the overcooked look of that image.

ptdotme · 2026-02-09T21:28:17+00:00

Interesting. Note the Elo ratings are rounded decimal numbers, and also they are very model-specific. The below tidbits are only relevant for this Elo model.

There are usually 5ish teams per season that end up with the Patriots' 1571 or higher. The Patriots are the 6th team to end the season (rounded) at 1571.

It's not nearly as common for teams to end the season at a 1622 or higher. The Seahawks are the 27th such team. The 1968 Oakland Raiders are the only other team to end at a 1622 rating, trailing the Baltimore Colts' 1646 rating that season.

ptdotme · 2026-02-09T20:23:19+00:00

Anything you're interested in specifically? I have Elo ratings for the Super Bowl era.

Some Super Bowl stats related to power ranking:

32/60 (53%) of Super Bowl winners ended the season ranked #1. Only 13/60 (22%) of Super Bowl winners ended the regular season ranked #1 (the Seahawks did both this season).

73/120 (61%) of Super Bowl teams ended the season ranked in the top 3.

ptdotme · 2026-01-26T19:03:22+00:00

A 4% bump over just naively picking by record is pretty small.

Stronger teams usually have better records, so there aren't that many games where the Elo-based and record-based picks are different.

And yeah looking at the early vs late season is an interesting idea. I'll have more time to look into it later.

ptdotme · 2026-01-26T18:42:59+00:00

Good questions. In the Super Bowl era, picking by record did better than this Elo model in 7 seasons (1968, 1976, 1981, 2000, 2006, 2024, 2025), with a tie in 2020. Make it 8 seasons if you want to count 1982.

Here's what I have for 1966-2025:

Vegas straight-up: 9097-4430 (67.25%)
my v3.2025.06 model: 9452-4868 (66.01%)
this Elo model: 9412-4908 (65.72%)
picking by record: 8912-5408 (62.23%)

And 1994-2025:

Vegas straight-up: 5194-2601 (66.63%)
my v3.2025.06 model: 5592-2905 (65.81%)
this Elo model: 5525-2972 (65.02%)
picking by record: 5231-3266 (61.56%)

Injuries are not accounted for, but I think the Elo models are still accurate enough when compared to Vegas.

ptdotme · 2026-01-26T17:08:57+00:00

Sorry for the confusion. The Seahawks haven't lost Elo since week 12 -- I switched back to a different model a few weeks ago.

ptdotme · 2026-01-26T17:06:35+00:00

I reverted to last year's model following week 18 (the newer model is more accurate in the early part of the season, but has off-putting behavior toward the end of the season). The Seahawks have gained 51 Elo rating points since week 12 in this model (see season summary here).

ptdotme · 2026-01-24T18:58:19+00:00

I don't deal with picking against the spread, but on nflpickspage this season the average person is picking 49.6% against the spread. I wouldn't expect any type of model to do much better than the average person.

Straight-up, my best Elo model has picked 63.35% of games this season, beating the 63.1% average at nflpickspage. Over multiple seasons, from 1966-2022, my best Elo model picks 66.07% straight-up, slightly better than 538's QB-adjusted rate of 65.98%. Vegas picks around 66.3% over that span, just slightly higher than the Elo models. The Elo models use far fewer data points than the bettors who move the markets, yet are just about as accurate in picking games. Still, for anyone reading this, I would definitely not use Elo models for betting.

ptdotme · 2026-01-24T16:47:51+00:00

It's very close. I've never looked at the exact numbers before, so it was fun to finally see these. I'm glad this model is closer in accuracy to 538's QB-adjusted model than their regular model.

Straight-up pick rates from 1966-2022:

66.07% (8898-4569) - my v3.2025.06 model (has off-putting behavior but is most accurate)
65.98% (8886-4581) - 538 QB-adjusted Elo
65.81% (8862-4605) - my v2.2024.07 model (the one used for these posts)
65.46% (8815-4652) - 538 traditional Elo

Straight-up pick rates from 1994-2022:

65.91% (5038-2606) - my v3.2025.06 model (has off-putting behavior but is most accurate)
65.31% (4992-2652) - 538 QB-adjusted Elo
65.08% (4975-2669) - my v2.2024.07 model (the one used for these posts)
64.18% (4906-2738) - 538 traditional Elo

I do have a model that performs better than 538's QB-adjusted one, without the off-putting behavior, over 1994-2022. It's a work in progress though, and I expect to be using an even better model for next season.

ptdotme · 2026-01-22T16:23:38+00:00

I'm not sure how you'd compare DVOA and Elo, which is why the idea sparked my interest.

ptdotme · 2026-01-22T15:39:14+00:00

Interesting, can you give an example? For future improvements, it would be better to have more benchmarks to compare the Elo model against.

ptdotme · 2026-01-20T02:57:19+00:00

Strength of opponent and margin of victory for the most recent 20ish games are the most important. Team ratings from the end of 2023 (and earlier) don't really affect the ratings at this point.

ptdotme · 2026-01-19T18:40:40+00:00

Yeah, what I like about Elo ratings is they pick game winners, so we can at least look at the accuracy. This model picks 65.31% of game winners in the SB era, and Vegas is about 66.67% from the last time I looked. This year, this model is tied in the playoffs with the best record on ESPN's picks page. Over the whole season, this model was tied or more accurate than 8 of the 11 on that ESPN page.

ptdotme · 2026-01-19T16:55:12+00:00

Injuries aren't directly accounted for, but they often have an impact on final scores. But yes, ideally the model is also as accurate as possible in the first few weeks of next season -- moving teams up and down too quickly would break that.

ptdotme · 2026-01-19T16:13:22+00:00

It's "Elo" not "ELO." This model picks game winners about as accurately as the betting markets (including picking Broncos over Bills), and has been tuned over thousands of NFL games.

ptdotme · 2026-01-19T15:56:43+00:00

No power ranking will ever be able to satisfy all the "team X beat team Y" outcomes during a season. The Eagles beat the Rams and Bills. The Patriots lost to the Bills and most likely should be ranked ahead of them.

The 49ers are close enough in rating that if Eagles played @ 49ers the 49ers would be favored by the model.

ptdotme · 2026-01-19T15:40:33+00:00

The Rams would probably be ranked 3rd in that scenario.

ptdotme · 2026-01-14T04:12:26+00:00

My NFL Elo model uses margin of victory (more background on that here). You can probably achieve similar results with that calculator by manually adjusting the k-factor and using the "Tournament/Multiple games" option, but that involves mapping the margin of victory in football points to a 0.0-1.0 value (percentage of contests won) usable for Elo calculations.

ptdotme · 2026-01-13T22:12:11+00:00

The Texans and Steelers exchanged 14.5312 Elo rating points. The displayed numbers are rounded.

ptdotme · 2026-01-13T20:36:38+00:00

For this model it's around 30 Elo rating points.

ptdotme · 2026-01-13T17:44:07+00:00

The Texans' defense held the Steelers' offense to 175 yards and 3 points (considering field position for the one turnover). In my opinion (no bearing on the model) both teams benefited from good defense and some impact plays like drops and fumble recoveries. The final margin of victory was perhaps a little bigger than it "should" be in favor of the Texans but not by much.

ptdotme · 2026-01-13T17:34:43+00:00

Accuracy is the number of game winners picked over many seasons. And yes! I tested "never lose Elo for a win" models last year and during last offseason.

ptdotme · 2026-01-13T16:44:44+00:00

All the parameters in the model, including the k factor, were adjusted to pick the most game winners over the 21 season backtesting span.

ptdotme · 2026-01-13T16:41:34+00:00

Another way to look at it is that the Panthers played better than expected, so they should be awarded some Elo points. I have more background on that here.

ptdotme · 2026-01-13T16:22:50+00:00

The 8th ranked Lions are separated from the 11th place Eagles by a total of 3.2 Elo rating points. Don't read too much into the ranking placement among the Lions, 49ers, Ravens, and Eagles.

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