Research on Competitive Balance in the Open League: Measuring the Trends in the Competitive Balance of the J. League Division 1

In this research, we focused on the competitive balance in the open league. We aimed to find out the effect of the league system’ s change, with or without new entries, and find out the relationship between wages and competitive balance. This research analyzed the J. League (Japan Professional Football League) , which changed from a closed league to an open league, and the English Premier League, which changed the revenue structure and increased its turnover in recent years. To measure competitive balance, we used the Herfindahl Index of Competitive Balance (HICB) , the Five Club Concentration Index of Competitive Balance (C5 index) . As a result, it was found that in the Premier League, competitive balance has declined in recent years. But in the J. League, on the other hand, after 1999, the year that the Second tier (J2) was made and the League adopted the promotion and relegation system, competitive balance slowly increased. Imbalance of Wages in the Premier League was substantially larger than in the J. League. From these results, we made a suggestion that adoption of a promotion and relegation system is one of the factors which improve competitive balance.