M Cattelan, C Varin and D Firth
Dynamic Bradley-Terry modelling for sports tournaments
Date: February 2012
Abstract: In the course of national sports tournaments, usually lasting several months, it is expected that the abilities of teams taking part in the tournament change in time. A dynamic extension of the Bradley-Terry model for paired comparison data is introduced to model the outcomes of sporting contests allowing for time-varying abilities. It is assumed that teams' home and away abilities depend on past results through exponentially weighted moving average processes. The proposed model is applied to sports data with and without tied contests, namely the 2009-2010 regular season of the National Basketball Association tournament and the 2008-2009 Italian Serie A football season.
Keywords: Bradley-Terry model; Cumulative logit model; Exponentially weighted moving average process; Paired comparisons; Sport tournaments.