Domestic matters: The evolution of competitive balance in New Zealand rugby's national provincial first division

Abstract

Previous literature on competitive balance in the First Division of the National Provincial Championship (NPC) has found the Division is becoming increasingly imbalanced. This dissertation extends the analysis of competitive balance in the NPC back to the inaugural competition (previous studies have only gone as far back as 1992) to ascertain if this increasing imbalance is a relatively recent phenomena or part of a longer term trend. We also investigate other dimensions of competitive balance that have not been studied before in the NPC context (specifically a temporal dimension, that is, the extent to which teams stay strong between seasons), using various economic and statistical tools. We show that one measure of competitive balance; the Herfindahl-Hirschman Index, is sensitive to Division size changes, and therefore must be modified. This has been overlooked in the previous literature. Using our measures we generally find that the Division is becoming more imbalanced, although part of our analysis shows that this trend may have abated since the early 1990s. This backs up the Competitions Review's findings and therefore provides support for the New Zealand Rugby Union's planned changes to the competition.