WHPUOS is an acronym for Worked Hours Per Unit Of Service —an operational efficiency statistic that expresses the relationship between worked hours and service volumes logged during a defined period of time (e.g., shift, day, per period)—and are always stated in hours or percentage of an hour. For example, a WHPUOS of 0.25 represents 25 percent of an hour. WHPUOS are not rates per hour, nor should they be confused with Workload Indicators or RVUs (relative value units). WHPUOS are a measure of labor intensity or staffing resources required per unit of service delivered. As such WHPUOS provides management with critical insight into staffing patterns, costs and variances.