CONCINDC: Stata module to calculate concentration index with both individual and grouped data

Zhuo Chen, The University of Chicago

Abstract

oncindc computes the concentration index (CI) for micro data with a categorical welfare variable or grouped data. See Kakwani, Wagstaff and van Doorslaer (1997). Note that although it was originally designed for microdata with a categorical welfare variable, it can handle grouped data and microdata with actual (not categorical) welfare variable. They could be treated as a special case of microdata with categorical welfare measure: there is only one observation for each category. For grouped data, since the program can handle frequency weight, the group sizes can essentially be treated as frequency weights. The program also can use standard error of group means of the health outcome if supplied. If not, it will be estimated as the standard deviation of health outcomes.