A Template for a Capstone Statistics Project Based on Bradley-Terry Models

• Activity Number: 342
• Type: Contributed
• Date/Time: Tuesday, August 5, 2014 : 10:30 AM to 12:20 PM
• Sponsor: Section on Statistical Education
• Author(s): Robin Lock*+
• Companies: St. Lawrence University
• Keywords: Bradley-Terry ; capstone ; sports ; education

Abstract

ASA guidelines for an undergraduate statistics major recommend that, when feasible, students have some sort of capstone experience to pull together various topics they have studied to address questions in a practical setting. We describe a general template for one such project - using Bradley-Terry models to rank sports teams or players. Based on a set of pairwise comparisons (game or match results), the goal is to produce a relative ranking of the teams/players and compute probabilities of outcomes for future contests. We discuss some ways to scrape past game results from the web to form a database, use software (in R) to fit the model, and then transform the results into interpretable ratings. Extensions of the model can account for ties, home advantage, or other characteristics of a particular sport, depending on the ability/background of the student.