A translog function is specified to represent the relation between revenue and human resource inputs in public accounting firms. Estimation of the model using a balanced panel of annual data for 64 large CPA firms for the period 1995–1999 indicates that increasing returns to scale prevail in the public accounting industry, justifying recent merger and acquisition activities among accounting firms. Average marginal revenue product of partners increased monotonically from 1995 to 1998, decreased slightly in 1999, and was about nine times that of other professionals during 1995–1999. The public accounting industry exhibited continuing improvement in productivity over the 5 years.

A fundamental assumption in cost accounting is that the relation between costs and volume is symmetric for volume increases and decreases. In this study, we investigate whether costs are “sticky”—that is, whether costs increase more when activity rises than they decrease when activity falls by an equivalent amount. We find, for 7,629 firms over 20 years, that selling, general, and administrative (SG&A) costs increase on average 0.55% per 1% increase in sales but decrease only 0.35% per 1% decrease in sales. Our analysis compares the traditional model of cost behavior in which costs move proportionately with changes in activity with an alternative model in which sticky costs occur because managers deliberately adjust the resources committed to activities. We test hypotheses about the properties of sticky costs and how the degree of stickiness of SG&A costs varies with firm circumstances.