| 来源类型 | Working Paper |
| 规范类型 | 报告 |
| DOI | 10.3386/w26512 |
| 来源ID | Working Paper 26512 |
| The Surprising Hybrid Pedigree of Measures of Diversity and Economic Concentration | |
| Paolo M. Adajar; Ernst R. Berndt; Rena M. Conti | |
| 发表日期 | 2019-12-02 |
| 出版年 | 2019 |
| 语种 | 英语 |
| 摘要 | Measures of economic concentration, such as the k-firm concentration index and the Hirschman-Herfindahl Index (HHI) are commonly used to ascertain the competitiveness of a product market. Within a Cournot model industry equilibrium, it is known a relationship exists between the HHI and the gap between industry price and marginal cost, but the economic theory foundations and intuition underlying the HHI formula are seemingly arbitrary. Here we document that there are indeed powerful and intuitive theoretical foundations to the HHI, but those foundations emanate from outside economics, namely, ecology, where the HHI is known as Simpson’s Diversity Index. We discuss the origins of the HHI and Simpson’s Diversity Index, summarize other measures of concentration, and link them to common measures of inequality. Based on a priori reasoning, we conclude there is little on which to base a choice between the HHI and non-HHI measures of market concentration. We empirically illustrate the implementation of the HHI and other concentration indexes as the statin drug LipitorTM lost patent protection and faced generic competition in 2012; we find very similar empirical trends and high correlations among them. Our research provides support for the continued use of HHI as a measure of concentration, provided one recognizes its link to market power is equivocal. |
| 主题 | Other ; History of Economic Thought ; Econometrics ; Estimation Methods ; Microeconomics ; Households and Firms ; Market Structure and Distribution ; Health, Education, and Welfare ; Health ; Law and Economics ; Industrial Organization ; Market Structure and Firm Performance ; Antitrust ; Regulatory Economics |
| URL | https://www.nber.org/papers/w26512 |
| 来源智库 | National Bureau of Economic Research (United States) |
| 引用统计 | |
| 资源类型 | 智库出版物 |
| 条目标识符 | http://119.78.100.153/handle/2XGU8XDN/584184 |
| 推荐引用方式 GB/T 7714 | Paolo M. Adajar,Ernst R. Berndt,Rena M. Conti. The Surprising Hybrid Pedigree of Measures of Diversity and Economic Concentration. 2019. |
| 条目包含的文件 | ||||||
| 文件名称/大小 | 资源类型 | 版本类型 | 开放类型 | 使用许可 | ||
| w26512.pdf（969KB） | 智库出版物 | 限制开放 | CC BY-NC-SA | 浏览 | ||
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