Do Firms Differ Much?
利用得克萨斯州多银行控股公司的面板数据，通过方差分析发现企业效应对盈利能力的决定作用大于市场效应，且效应大小随时间变化。
With finn profitability data for a cross-section of geographic markets, it is possible to determine the relative importance of firm and market effects on profitability . Analysis of variance from a panel of multihank holditig companies in Texas suggests that finn effects are more important than market effects in determining profitability, and that the magnitudes of the effects vary over time. IN A 1985 article, Schmalensee takes a new approach to analysis of the structure-conduct-performance paradigm. Schmalensee chooses a purely descriptive approach to distinguish among the classical tradition of Bain [1956], which takes markets as the basic unit of analysis, with a particular focus on market concentration; the revisionist views of Demsetz [1973] and Peltzman [1977], who view the observed relation between profitability and concentration as reflecting underlying inter-firm profitability differences; and the managerial view, that profitability is determined by firm-wide management practices, but not necessarily by differences in market share. This descriptive approach has two advantages over a structural analysis. A descriptive analysis avoids imposition of the troublesome maintained hypotheses inherent in structural models. Further, as Scott and Pascoe [1986] point out, the explanatory power of structural models is generally only a small fraction of that of descriptive models.