Comparing competitive balance in Australian sports leagues, the AFL, NBL and NRL: does the AFL's team salary cap and player draft measure up?

In the period following the introduction by the Australian Football League (AFL) of the team salary cap in 1985 and the player draft at the end of 1986, within-season competitive balance (measured by the seasonal distribution of team win percents) has increased. This paper continues the investigation into whether the improvement in competitive balance in the AFL can be attributed to these labour market changes by examining competitive balance outcomes and labour market changes in two other Australian sports leagues, the National Basketball League (NBL) and the National Rugby League (NRL). The measurement of competitive balance in this paper is extended to include a simple measure of between-season competitive balance, namely the distribution of championships/premierships amongst teams/clubs. The evidence suggests that since 1985 within-season competitive balance (measured by ASD/ISD ratios) has increased slightly in all three leagues, and both pre- and post-1985 the NRL has been the most balanced and the NBL the least balanced. The distribution of championships/premierships is, in general, also more even in the period post-1985 period in all three leagues. The most significant labour market change in both the NBL and the NRL post-1985 is their adoption of a team salary cap. Thus, the evidence on competitive balance is not inconsistent with the view that the introduction of a team salary cap (at least) in all three leagues has improved competitive balance since 1985. However, since 1985 there has also been net expansion in the number of clubs/teams in all three leagues, and a considerable turnover in both the NBL and the NRL, but not the AFL. The expansion and contraction of the leagues is compared with changes in their competitive balance, leading to the conclusion that the number and, in particular, the location of teams/clubs is also likely to have been another major influence on competitive balance.