Clint Jowett

Offlode / Massey University

Quantifying the division between professional and amateur rugby in New Zealand

This is joint work with Paul J. Bracewell, Daniel C. Walsh and Don G. R. Forbes

Team Lodeings are a useful rating method for measuring intra-competition team performance. This method is based on relative points differential. However, these ratings are not suitable for use when inter-competition matches are played and the ability levels on the distinct competitions cannot be assumed to be equivalent. We develop a method for calibrating intra-competition ratings so that they become meaningful inter-competition ratings. We test and validate our approach using the American domestic gridiron competition (NFL) before applying the results to New Zealand domestic first class rugby. Using the calibrated inter-competition Team Lodeings we will outline how the game of rugby has evolved in New Zealand over the last 30 years.