Competition: Theoretical paramaterizations and empirical measures

This paper proposes relative profits (RP) as a robust measure of competition. I consider nine different parameterizations of competition and show that more intense competition increases the profits of a firm relative to a less efficient firm. Further, popular competition measures like the price-cost margin (PCM) and Herfindahl index (H) can either increase or decrease in response to more intense competition. In this sense, RP is a more robust competition measure than PCM and H.