Absolute and Relative Concentration in United States Retailing
研究了美国零售业集中度的变化，发现尽管大型零售企业增长、小商店减少，但基尼系数显示集中度仅小幅上升，竞争受公司规模趋势影响很小。
Dr. Alvin D. Star is associate dean at the College of Business Administration, University of Illinois at Chicago, U.S.A., and Anthony Robinson is with the Office of Advocacy of the United States Small Business Administration. Highly visible growth of large scale retail companies and a contemporary decline in the number of small retail shops in the U.S. suggests a large increase in U.S. retail industry concentration. However, a relative measure of concentration, the Gini co-efficient, indicates on a small increase from 1958 to 1977. Structurally, the industry changed only as if each retail company almost doubled in employment size over the time period. Therefore retail competition is little affected by recent company size trends.