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*Preliminary NSFL ELO Ratings - Beaver - 11-15-2017 I'm posting this in the hopes of getting some feedback to improve the methodology so if you have any suggestions or questions I'd love to hear them and if you see anything that looks glaringly wrong point it out because there is a non-zero chance that I fucked up somewhere along the line. These are far from being finished (see the last section for some of the flaws) so don't get too butthurt if you think your team is lower than it should be, etc. Alright so I've been working through historical ELO Ratings for the NSFL and I've settled on these parameters for now:
![]() The line graph looked ugly as sin when I had bye weeks as breaks in the lines so the flat parts of the lines are typically when teams aren't playing. (PS: I hate whoever's idea it was to have bye weeks in Season 2) S1W1 = Season 1 Week 1 S1P1 = Season 1 Playoff Round 1 Considering this is just preliminary I didn't fancy up the graph too much (x axis labels are uggo and I'm going to emphasize the demarcation between seasons more in the final version). Current ELO Ratings: 1. Arizona - 1771 2. Orange County - 1628 3. Baltimore - 1571 4. Yellowknife - 1499 5. San Jose - 1490 6. Philadelphia - 1472 7. Las Vegas - 1329 8. Colorado - 1238 Some fun facts (keep in mind this is based on preliminary numbers):
GRADED *Preliminary NSFL ELO Ratings - 7hawk77 - 11-15-2017 Excellent write up. Well done! *Preliminary NSFL ELO Ratings - ErMurazor - 11-15-2017 Nice. I like this. You should include Arizona' preseason S1 ELO of -9000. *Preliminary NSFL ELO Ratings - bovovovo - 11-15-2017 This is very awesome. I love the graph, I'm a sucker for data visualization ![]() I do think it's important to incorporate home field advantage because we know the sim puts a lot of value in it. (11-15-2017, 06:19 PM)Beaver Wrote:Yellowknife has lost as a favorite 16 times, most in the NSFL This confirms my world view *Preliminary NSFL ELO Ratings - manicmav36 - 11-15-2017 This is awesome stuff! I'd love to see this through the end of the season. I imagine things will change quite a bit when you include home-field advantage. *Preliminary NSFL ELO Ratings - AdamS - 11-15-2017 hot damn that's good work *Preliminary NSFL ELO Ratings - 37thchamber - 11-16-2017 I suspect your k factor is a little on the high side. An 80 pt gain is a 160 pt swing. That's way too much variance for one result IMO and a possible cause for rank inflation. This would also allow you to weight playoff games more. I'd probably go for 24 in the regular season and 32 in the playoffs. Just need to make sure your margin of victory adjustments don't allow it to extend beyond those limits probably. Home advantage is also a must. In any implementation of the Elo rating system where home field is a factor, it is used (typically by adjusting rankings in the calculation) because it hurts the rating system to exclude it (and you get rank inflation). I'd suggest a rank advantage of about 150 pts as a test. I think it was JuOSu who did it before but can't remember what adjustment was made. Solid stuff though. You beat me to it with the margin of victory implementation (I was planning to use a variant of the system used for soccer) which was one of the things I noted as being missing from the last implementation we saw of Elo here. (Also why does everyone call these ELO ratings? It's Elo. Elo is a dude's name.) *Preliminary NSFL ELO Ratings - ADwyer87 - 11-16-2017 holy jamoly *Preliminary NSFL ELO Ratings - JuOSu - 11-16-2017 Excellent stuff, though I disagree with some of your choices. You should go back and read my first post of my ELO ratings to see some of the different numbers I used. Otherwise great work. *Preliminary NSFL ELO Ratings - Beaver - 11-16-2017 Thanks everybody, this is definitely a work in progress but it's a fun little project to play around with. (11-16-2017, 03:39 AM)37thchamber Wrote:I suspect your k factor is a little on the high side. An 80 pt gain is a 160 pt swing. That's way too much variance for one result IMO and a possible cause for rank inflation. This would also allow you to weight playoff games more. I'd probably go for 24 in the regular season and 32 in the playoffs. Just need to make sure your margin of victory adjustments don't allow it to extend beyond those limits probably.Yeah that makes sense. I went with a k factor of 20 as a starting value since that's about what real life sports tend to be around so I think that 160 point swing was either just a massive outlier or my MOV adjustment is too lenient - bumping the k factor up to 24 turns that into a 192 point swing. The mean swing with these numbers is 42 points with a standard deviation of 32 so that 160 point swing was 3 and a half standard deviations above average. That standard deviation is a bit high for my liking but I'll revisit this after I make the adjustments, especially home field, as making the k value more precise is one of my priorities going forward. (11-16-2017, 03:39 AM)37thchamber Wrote:Home advantage is also a must. In any implementation of the Elo rating system where home field is a factor, it is used (typically by adjusting rankings in the calculation) because it hurts the rating system to exclude it (and you get rank inflation). I'd suggest a rank advantage of about 150 pts as a test. I think it was JuOSu who did it before but can't remember what adjustment was made.Yeah, this started out as an SHL project where I don't think there's a home advantage and I just completely blanked on including it. Unfortunately I'm a fairly casual NSFL member so I'm not super familiar with the sim we use. It looks like in an evenly matched game having home field would make win probability increase from 50% to 70% with a 150 point adjustment. Does that sound about right with the way the sim works? Time to do some testing. (11-16-2017, 03:39 AM)37thchamber Wrote:Solid stuff though. You beat me to it with the margin of victory implementation (I was planning to use a variant of the system used for soccer) which was one of the things I noted as being missing from the last implementation we saw of Elo here.I leaned heavily on this article (among others) in developing this and based my margin of victory adjustment on theirs (specifically footnote 2). This was fortunate for me because I had originally planned on going with something similar to the soccer system but I didn't really want a piecewise function out of my own laziness. (11-16-2017, 03:39 AM)37thchamber Wrote:(Also why does everyone call these ELO ratings? It's Elo. Elo is a dude's name.)That's a very good question. Habit, I suppose ![]() (11-16-2017, 05:15 AM)JuOSu Wrote:Excellent stuff, though I disagree with some of your choices. You should go back and read my first post of my ELO ratings to see some of the different numbers I used. Otherwise great work.As usual you beat me to it lmao. I'll definitely dig that up, appreciate the heads up. |