The Number of Firms and Production Capacity in Relation to Market Size
研究了瑞典250个地区驾校市场中企业数量和生产能力与市场规模的关系，发现企业数量随市场规模增加但比例递减，且大市场中单位产能的市场规模更小，表明人均利润随市场规模递减。
Many oligopoly theories predict a positive correlation between market size and the equilibrium number of firms and some also imply that competition is more intense in larger markets. We test these predictions on a sample of driving schools in 250 Swedish regional markets by estimating the relation between the number of firms, production capacity, and market size. The number of firms increases less than proportionally with market size. Market size per capacity unit is smaller in large markets. Since firms produce a fairly homogenous good, we argue that this is evidence that profits per capita is decreasing in market size.