The Work Productivity Short Inventory (WPSI), also known as the Wellness Inventory, was developed to quickly assess the prevalence of medical problems that may influence work productivity and the financial implications of those problems. The WPSI asks respondents to note the amount of time missed from work resulting from 15 medical conditions and the amount of unproductive time spent at work when affected by the condition. Three versions of the WPSI were compared that differed according to the length of the recall period (12 months, 3 months, or 2 weeks). The reliability of the financial metrics generated from the WPSI was assessed for each version and found to be adequate, ranging from 0.66-0.74 in this application. The WPSI was found to be a highly reliable tool for estimating the prevalence of medical conditions that influence work productivity. The dollar impact of the associated productivity losses were found to be reliable enough to meet the instrument's intended purpose, which is to help employers understand relationships between disease and productivity, thereby contributing to the design of interventions to relieve these problems. The needs of the researcher should dictate which version of the WPSI to use.