This study demonstrates that on psychiatric inpatient units, the amount of direct social work time spent per patient is strongly correlated with one major variable, the patient turnover rate. Calculating the parameters of this relationship for a given facility permits the administrator to use turnover rate as one important factor in understanding social work staffing requirements. The correlation between turnover rate and direct care time allows a fair quantitative comparison of workloads among disparate units and offers an empirical tool for determining the number of cases which can be carried by each staff member. Examples are given to illustrate how the correlation found can be used both to demonstrate staffing needs and as one factor in setting quantitative norms for social work performance. This system meets with little staff resistance because it is based on data from actual practice and can therefore be modified to take into account unique circumstances within the particular institution.