Is there a tendency for profits to equalize?

Epstein states that there is little tendency for rates of profits in different industries to become equalized, even if allowance is made for different degrees of risk. But his conclusions rest on a sample of large and successful corporations during eight years only. Profits as reported are frequently not fairly comparable because of differences in accounting methods and in capital set-up. Moreover, taxes should be deducted from reported profits, and they were not uniform. High rates of average profit usually go hand-in-hand with great variability in profits from year to year. Readjustments among industries are most apt to occur in years of business recession, but were nevertheless considerable even before 1929.