Cohort Turnover and Operational Performance: The July Phenomenon in Teaching Hospitals

We consider the impact of cohort turnover—the planned simultaneous exit of a large number of experienced employees and a similarly sized entry of new workers—on operational performance in the context of teaching hospitals. Specifically, we examine the impact of the annual July turnover of residents in U.S. teaching hospitals on the average length of hospital stay and mortality rate in teaching hospitals relative to a control group of non-teaching hospitals. Despite the anticipated nature of the cohort turnover and the supervisory structures that exist in teaching hospitals, the annual July turnover of residents results in increased resource utilization (i.e., longer average length of stay) for both minor and major teaching hospitals, relative to a control group of non-teaching hospitals. We find limited evidence of negative effects on quality as measured by mortality rates. In major teaching hospitals, we find evidence of a substantial anticipation effect that presents as a gradual decrease in operational performance beginning several months before the actual cohort turnover. We identify higher overall quality of nursing and increased intensity of potential quality assurance as managerial levers for mitigating the decrease in hospital operational performance both at the time of and in the months leading up to the cohort turnover.