## Calculating herfindahl index in stata

The Herfindahl-Hirschman Index is an index that measures the market concentration of a given industry. A highly concentrated industry is one where only a few players in the industry hold a large percentage of the market share, leading to a near-monopolistic situation. This video shows how to calculate the HHI using several examples. Herfindahl-Hirschman Index (HHI): Measuring Market Concentration Economics in Many Lessons. The Herfindahl-Hirschman Index (HHI) is a commonly accepted measure of market concentration. It is calculated by squaring the market share of each firm competing in a market and then summing the resulting numbers. It can range from close to zero to 10,000.

HHI: Stata module to compute Herfindahl index by(varlist) [if exp] [in range] [ outfile, replace] Description: hhi generates Herfindahl-Hirschman index variables   In other words, the Herfindahl index is calculated for each farm separately simultaneously obtained using STATA and are reported in Tables 5 and 6. Both half  Stata do file for Figure 1.1 can be found at “Chapter1\Applications\1_comparing If concentration indices such the Herfindahl index are calculated over active  1 Jan 2015 Tabmiss, summarizing missing data in Stata. betaprior Module to calculate the parameters of a Beta distribution given the mean and hurdle regression hhi Module to compute Herfindahl index hildasetup Module to create  Ellison and Glaeser interpret their index by calculating the values for industries. 30 is the plant Herfindahl index for that industry and zk is plant k's share of. 23 Oct 2019 HHI_CR35 is the Herfindahl-Hirschman index, and the concentration ratio Source: Authors' calculation from BankScope, using Stata 12.

## Basically the Herfindahl index is an indicator of the level of competition of a given market. Therefore you must have just one value for this index to characterize a given market (it does not vary across companies on this market). When you use the commands I wrote you do end up with one observation corresponding to the index for your dataset.

hhi5 generates Herfindahl-Hirschman index (HHI) variables also commonly known as concentration index in economics and finance. The module supports multiple variables and group ids and allows user to export output in table format (csv comma delimited). Since 1982, the U.S. Department of Justice, the Federal Trade Commission, and state attorneys general have used the Herfindahl-Hirschman Index (HHI) to measure market concentration for purposes of antitrust enforcement. The HHI of a market is calculated by summing the squares of the percentage market shares held by the respective firms. Academia.edu is a platform for academics to share research papers. where, say, the value 1600 is obtained using the formula (si*100)^2, where si is the share of importer11 in item1 and is obtained using 10/25, 25 is the sum of all entries in item1. This will allow me to get the Herfindahl-Hirschman index by importer for each item. I hope any one of you can help. Thank you so mcuh.

### 10 We perform all estimations in Stata. We fit SUR through the command This is calculated as the inverse of the Herfindahl-Hirschman Index. (HHI) based on

{p2col :{hi:hhi5} {hline 2}}generates Herfindahl-Hirschman index (HHI) with the highest top # values of each variable in {varlist} to calculate the HHI index. { stata "hhi5 sale hour, by(industry race) prefix(hhi5) top(5) minobs(10)":hhi5 sale