KRACH Formula

[jfgreco]

https://atlantichockeyfederation.com/federation-krach-update/

They intend to publish the formula. Also indicated that there was an issue with shootouts. This might help get this closer.

[jasonfsmitty]

Awesome, thanks for the update!

[jfgreco]

https://atlantichockeyfederation.com/krach-explained/

[jasonfsmitty]

Finally had some time this weekend to dig into this proper. The code referenced by the AHF (https://github.com/bjlkeng/Bradley-Terry-Model) requires some modifications to get the AHF results. I'll create a fork with my changes for those interested.

This tool has been updated to properly mirror the AHF algorithm, and all of the standings have been re-calculated. I'd like to update all of the documentation, but that may or or may not get done this weekend.

Note that even with the changes, there are still some minor differences. In the 14U AA division (which has been my focus since that's where my son plays) most teams are identical to the AHF published numbers, but there are still 3 teams with different ratings. Any tweaks I've tried to make have ripple changes through all teams, making the overall ratings more different. For example, if I assume one of the games was entered wrong into the system and swap winner/loser, it'll ripple through the strength-of-schedule changing everyone's rating.

Once the remaining updates are done (docs for this tool, fork of the AHF tool) I'll communicate with the AHF and see if they can help me iron out the last few differences.

[jfgreco]

Thanks for the time you put in. I like you was only focusing on one division 10UB. Everything I looked at was pretty darn close. There were a handful that were off by a point. I wonder what is the differences in those cases.

[jfgreco]

Rank	Calc KRACH	AHF KRACH	+/-	Subdivision	Team	GP	W	L	SOW	SOL	T	SoS	Exp Wins	Win Diff
1	3195	3187	-8	Championship	Jersey Shore Wildcats Black	17	16	0	0	0	1	181	16.8	0
2	1030	1029	-1	Championship	Philadelphia Jr. Flyers	37	31	3	2	0	1	192	33.8	0
3	505	506	1	Championship	Wissahickon Warriors Red	37	28	7	0	1	1	324	28.8	0
4	221	221	0	Championship	NJ Bandits Red	17	10	6	0	0	1	698	10.8	0
5	197	198	1	Gold	Haverford Hawks Schneider	37	24	12	0	0	1	391	24.9	0
6	163	163	0	Gold	Igloo Jaguars	39	25	10	2	1	1	238	27.9	0
7	159	159	0	Gold	Frederick Freeze	17	12	3	1	0	1	155	13.9	0
8	117	117	0	Gold	Hollydell Hurricanes	37	25	8	1	2	1	181	26.9	0
9	96	96	0	Silver	Delaware Ducks Black	37	20	14	1	1	1	171	21.9	0
10	90	88	-2	Silver	York Devils	37	23	10	3	0	1	116	26.9	0
11	86	86	0	Silver	Royals Gray	37	24	12	0	0	1	184	24.9	0
12	77	78	1	Silver	North Jersey Sportscare Kings Yellow	17	6	9	1	0	1	536	7.9	0
13	55	55	0	Bronze	Valley Forge Colonials 10U B Skelton	37	15	19	1	1	1	353	16.9	0
14	47	47	0	Bronze	Southern Maryland Sabres 10U Black	17	9	7	0	0	1	61	9.9	0
15	37	37	0	Bronze	Royals Gold	37	15	18	0	3	1	300	15.9	0
16	34	35	1	Bronze	Lehigh Valley Phantoms	37	19	13	1	3	1	150	20.9	0
17	20	20	0		Lancaster Firebirds	38	10	25	1	1	1	167	11.9	0
18	20	20	0		Team Philadelphia	37	13	22	0	1	1	85	13.9	0
19	18	18	0		Haverford Hawks Wharton	37	15	21	0	0	1	138	15.9	0
20	16	16	0		Jersey Shore Wildcats Red	17	7	9	0	0	1	46	7.9	0
22	14	15	1		MYHA 10U B Blue	17	3	13	0	0	1	129	3.9	0
21	14	14	0		Tomorrow's Ice North Stars White	17	6	10	0	0	1	45	6.9	0
23	12	12	0		Maryland Jr Black Bears Red	17	3	13	0	0	1	125	3.9	0
24	9	0	-9		Rockets Hockey Club White	37	7	28	1	0	1	480	8.9	0
25	8	8	0		NJ Bandits White	17	5	11	0	0	1	69	5.9	0
26	7	7	0		Wissahickon Warriors White	37	11	25	0	0	1	62	11.9	0
27	5	5	0		Grundy Senators	37	7	28	1	0	1	98	8.9	0
28	3	4	1		Philadelphia Blazers	37	5	27	1	3	1	157	6.9	0
29	0	0	0		Valley Forge Colonials 10U B Malik	37	0	36	0	0	1	124	0.9	0