Ranking and Measuring of Sailing Teams

Recently, the Rasch listserv (see www.rasch.org/rmt) has been discussing sports scoring and ranking using the Rasch Model. As the faculty coach for our sailing team for the last 6 years, I was interested that the only ranking of sailing teams was a coach's poll in Sailing World Magazine typically issued by 3 coaches. Clearly, the opportunity (and evidence) for bias and was the subject of much debate.

This issue came to a head about a year ago when 2 "at-large" berths were created at the Nationals with little factual information to use as the mechanism to add the last 2 teams to the district eliminations. The last team picked "at-large" won the national championship last year!

Scoring sailing is "as ordinal as you can get." Most contests are regattas with 2 to 4 divisions (A,B,C,D). Usually, one thinks of the A division as the best. The regatta consists of 4 to 36 races in a weekend between each division's competitors representing 4 to 20 teams.

A team's score is their ordinal place in each race added together at the end of the regatta. The lowest total wins, excluding tie-breakers, disqualifications and similar exceptions. No one cares if you win by 2 inches or 200 yards. The number of points doesn't always reflect skill, since strategy between divisions dictates sacrificing some points in a given division to ensure overall victory.

Rasch measures vs. Coaches' Poll

Last fall, I entered data on 71 regattas representing 142 teams into a Rasch analysis. Since regatta conditions vary widely by weather, type of boat, level of competition, and unknown factors, each regatta was a FACET you could call "harshness" or "difficulty" which represented the skill needed at that event.

The Figure contrasts the coach's poll and the Rasch measures for November, 2001. Old Dominion, OD,is ranked 2nd by the coaches, and 8th by Rasch. Brown, B, is ranked 13th by the coaches, and 5th by Rasch.

Along the top of the plot are teams unranked by the coaches, such as MIT, M, which is ranked 14th by Rasch. The Rasch results produced quite a conversation on the Internet and we're new collecting data for the spring season.

The Rasch measures are helpful in seeing distance between schools. The Rasch ranking of regattas made good sense to the sailors and they enjoyed that information. The biggest problem was the number of schools without common opponents or enough data to be measurable, such as Hawaii, ranked 8th by the coaches. Most schools were excited that Rasch measures were posted for all 142 teams.

Steve Lang

Ranking and Measuring of Sailing Teams. Lang S. … 15:4 p. 851

Ranking and Measuring of Sailing Teams Lang S. … Rasch Measurement Transactions, 2002, 15:4 p. 851

Rasch Books and Publications
Invariant Measurement: Using Rasch Models in the Social, Behavioral, and Health Sciences, 2nd Edn. George Engelhard, Jr. & Jue Wang	Applying the Rasch Model (Winsteps, Facets) 4th Ed., Bond, Yan, Heene	Advances in Rasch Analyses in the Human Sciences (Winsteps, Facets) 1st Ed., Boone, Staver	Advances in Applications of Rasch Measurement in Science Education, X. Liu & W. J. Boone	Rasch Analysis in the Human Sciences (Winsteps) Boone, Staver, Yale
Introduction to Many-Facet Rasch Measurement (Facets), Thomas Eckes	Statistical Analyses for Language Testers (Facets), Rita Green	Invariant Measurement with Raters and Rating Scales: Rasch Models for Rater-Mediated Assessments (Facets), George Engelhard, Jr. & Stefanie Wind	Aplicação do Modelo de Rasch (Português), de Bond, Trevor G., Fox, Christine M	Appliquer le modèle de Rasch: Défis et pistes de solution (Winsteps) E. Dionne, S. Béland
Exploring Rating Scale Functioning for Survey Research (R, Facets), Stefanie Wind	Rasch Measurement: Applications, Khine	Winsteps Tutorials - free Facets Tutorials - free	Many-Facet Rasch Measurement (Facets) - free, J.M. Linacre	Fairness, Justice and Language Assessment (Winsteps, Facets), McNamara, Knoch, Fan
Other Rasch-Related Resources: Rasch Measurement YouTube Channel
Rasch Measurement Transactions & Rasch Measurement research papers - free	An Introduction to the Rasch Model with Examples in R (eRm, etc.), Debelak, Strobl, Zeigenfuse	Rasch Measurement Theory Analysis in R, Wind, Hua	Applying the Rasch Model in Social Sciences Using R, Lamprianou	El modelo métrico de Rasch: Fundamentación, implementación e interpretación de la medida en ciencias sociales (Spanish Edition), Manuel González-Montesinos M.
Rasch Models: Foundations, Recent Developments, and Applications, Fischer & Molenaar	Probabilistic Models for Some Intelligence and Attainment Tests, Georg Rasch	Rasch Models for Measurement, David Andrich	Constructing Measures, Mark Wilson	Best Test Design - free, Wright & Stone Rating Scale Analysis - free, Wright & Masters
Virtual Standard Setting: Setting Cut Scores, Charalambos Kollias	Diseño de Mejores Pruebas - free, Spanish Best Test Design	A Course in Rasch Measurement Theory, Andrich, Marais	Rasch Models in Health, Christensen, Kreiner, Mesba	Multivariate and Mixture Distribution Rasch Models, von Davier, Carstensen

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