On the inherent bias in the 2011 and 2012 Super Rugby tournament format

Abstract


 Fifteen regional rugby union teams compete for the Super Rugby title – five each from Australia, South Africa and New Zealand. In 2011, significant changes were made to the tournament format and these were continued in 2012. The new changes created an inherent bias, favouring teams that are strong relative to their conference, regardless of their overall strength. It is shown using logic and numerical results from simulations that teams that are weaker are able to unfairly progress to higher positions on the competition log at the end of the ‘regular’ season. The bias arises as a result of teams playing more matches against teams within their conference than other teams within the competition, and therefore the final log position represents a team’s strength relative to their own conference more than their overall strength. In the face of this evidence the tournament format should be altered to re-align with the primary goal of determining the best team in the competition. Should the tournament organisers choose not to change the tournament format, it would not be unreasonable for them to face criticism for failing to implement measures to ensure fairness to each team within the competition.