Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This paper considers the extent to which the short-run dynamic behavior and long-run equilibrium levels of profitability differ among firms within the same industry. Movements in profits are modeled in terms of firm specific deviations from average industry profits, and industry specific deviations from economy-wide average returns. Applied to a sample of 217 large U.K. firms, 1951-77, the results suggest that considerable heterogeneities exist within most industries. That is, most firms' profitability experience differs considerably from those of their closest rivals. Copyright 1987 by Blackwell Publishing Ltd.