This paper compares market structure in different industries using conventional additive measures and various indices of firm size inequality. It is found that levels or changes in market structure are not exactly consistent across various measures. However, as compared to additive measures, inequality indices give more consistent results, and hence can be used to examine the structure of markets in different industries. Nonetheless, since there are inconsistencies across different inequality indices, efforts should be made towards formulating a suitable criterion for selecting the most appropriate measure.
