Arrigan Memorial Regatta — Analysis

Performance rating answers one question for each skipper: holding every other skipper's rating fixed, which rating makes my actual race-by-race finishes least surprising? It is the maximum-likelihood rating under the same Plackett–Luce model that produces the power rankings (how accurate it is), with each opponent fixed at their rating from the last rated week before this event (2025-W18). Substitute skippers are scored only on the races they sailed, and races the boat did not finish (OCS, DNF and similar) are left out.

Percentile places a rating among the 2,245 ICSA skippers who were rated within the year before this event, so it reads as “better than X% of the skippers racing in this league right now”. The arrow shows where the sailor stood going in and where this performance would put them.

Surprise is how many bits more surprising the sailor's finishes were at their pre-event rating than at their performance rating (0 = exactly as expected). P(this good or better) simulates the regatta 3,000 times with the sailor at their pre-event rating against the actual fleet, and reports how often they would score this many points or fewer in the races they skippered. Races in one regatta are not independent, so each simulation also gives every skipper a good or bad regatta, form that drifts from race to race, and the speed of each boat the rotation puts them in (why). Low means an unusually good regatta, high means an unusually poor one. It deliberately ignores how rivals actually sailed, so it agrees with the performance rating rather than with the division finish, which also depends on everyone else's day. Ratings are shown on the rankings scale (model rating × 100). Only skippers are rated; crews are not part of the model.

• ⁿ no rating before this event — the model's estimate from this week is used as the baseline.
• — in the performance column means the skipper finished last in every race they sailed, so no finite least-surprisal rating exists.

Fin	Skipper	School	Races	Rating before*	Perf. rating	Δ	Percentile before → perf.	Surprise (bits)	P(this good or better)	Avg finish actual / exp.	Rating after*
1	Mateo Di Blasi '25	Georgetown University Hoyas 1 A	2/3	439*	579	+140	98th → 99th	1.3	20%	2.0 / 4.2	438*
1	Caro Gaston '25	Georgetown University Hoyas 1 A	1/3	106n*	204	+98	50th → 70th	0.5	39%	5.0 / 7.1	106*
2	Jeffrey Petersen '25	Georgetown University Hoyas 7 A	2/3	395*	69	-326	96th → 42nd	8.1	87%	7.5 / 5.1	392*
2	Kelly Bates '26	Georgetown University Hoyas 6 A	2/3	374*	352	-22	94th → 92nd	0.1	78%	7.0 / 5.4	378*
2	Thomas Daniels '26	Georgetown University Hoyas 2 B	2/3	116n*	438	+322	52nd → 98th	6.2	6%	5.0 / 10.5	116*
2	Ellie Smith '28	Georgetown University Hoyas 7 A	1/3	92*	700+	+608	47th → 99th	4.0	5%	1.0 / 7.4	110*
2	Scarlett Harris '28	Georgetown University Hoyas 6 A	1/3	126n*	357	+231	55th → 92nd	1.6	18%	2.0 / 6.8	126*
2	Vaughn Slatoff '26	Georgetown University Hoyas 2 B	1/3	132n*	171	+39	56th → 63rd	0.1	53%	6.0 / 6.5	132*
5	Piper Holthus '25	Georgetown University Hoyas 4 A	2/3	412*	452	+40	97th → 99th	0.2	47%	4.0 / 4.7	414*
5	Colin Pryma '28	Georgetown University Hoyas 4 A	1/3	-113*	110	+224	7th → 51st	1.9	20%	9.0 / 11.6	-61*
6	Brady Read '28	Georgetown University Hoyas 5 B	2/3	188*	363	+176	66th → 93rd	2.5	26%	7.5 / 9.5	194*
6	Nathan Van Doorn '28	Georgetown University Hoyas 5 B	1/3	12*	290	+278	30th → 84th	2.4	9%	3.0 / 9.1	32*
7	Adelia Derose '26	Georgetown University Hoyas 3 B	1/3	150*	600	+450	59th → 99th	4.5	3%	2.0 / 10.2	166*
7	Isabel Massey '27	Georgetown University Hoyas 3 B	1/3	184n*	516	+333	66th → 99th	3.1	6%	3.0 / 9.5	184*
7	Meredith Monnich '27	Georgetown University Hoyas 3 B	1/3	51n*	—	—	38th → —	2.4	>99%	14.0 / 8.2	51*
8	Benjamin Smith '26	Georgetown University Hoyas 5 A	2/3	359*	317	-42	92nd → 87th	0.2	91%	9.0 / 5.8	376*
8	Abigail Chang '28	Georgetown University Hoyas 5 A	1/3	194n*	228	+34	68th → 75th	0.1	49%	4.0 / 5.2	194*
9	Peter Barnard '27	Georgetown University Hoyas 3 A	2/3	408*	336	-72	97th → 90th	0.8	93%	8.0 / 4.7	407*
9	Teddy Stoldt '28	Georgetown University Hoyas 3 A	1/3	87n*	149	+62	46th → 59th	0.2	50%	7.0 / 7.5	87*
10	Diego Escobar '25	Georgetown University Hoyas 2 A	2/3	421*	111	-309	98th → 51st	9.9	98%	9.0 / 4.6	420*
10	Margot Gordon '26	Georgetown University Hoyas 2 A	1/3	27n*	86	+58	33rd → 46th	0.2	60%	10.0 / 8.6	27*
11	Jake Julien '28	Georgetown University Hoyas 6 B	2/3	231*	287	+56	75th → 83rd	0.3	81%	11.0 / 8.7	245*
11	Maya Luthi '27	Georgetown University Hoyas 6 B	1/3	124n*	120	-4	54th → 53rd	0.0	65%	8.0 / 6.7	124*
12	Alexa Shea '26	Georgetown University Hoyas 4 B	2/3	189*	298	+109	67th → 85th	1.1	56%	10.0 / 9.6	205*
12	Jack Duffy '27	Georgetown University Hoyas 4 B	1/3	152*	44	-108	59th → 37th	1.0	93%	11.0 / 5.9	159*
13	Meredith Kean '26	Georgetown University Hoyas 7 B	2/3	91n*	288	+197	47th → 83rd	3.0	39%	10.5 / 10.9	91*
13	Jack Pryma '26	Georgetown University Hoyas 7 B	1/3	102*	-16	-117	50th → 24th	1.1	97%	13.0 / 7.2	104*
14	Anson Walker '25	Georgetown University Hoyas 1 B	2/3	76*	269	+193	43rd → 81st	3.0	55%	12.0 / 11.5	90*
14	Poshu Ng '27	Georgetown University Hoyas 1 B	1/3	114n*	27	-87	52nd → 33rd	0.6	90%	12.0 / 7.0	114*