Does What Happens in the ED Stay in the ED? The Effects of Emergency Department Physician Workload on Post-ED Care Use

Emergency department (ED) crowding has been a persistent concern in the U.S. healthcare system. As such, many researchers have studied its effects on outcomes within the ED. We present novel results regarding the impacts of ED crowding on system performance outside the ED, specifically post-ED care utilization. We show that there is an increasing concave relationship between ED physician workload and post-ED care use. When workload increases from its 5th percentile to the median, the number of post-discharge encounters for discharged patients increases by 5%. Further, we identify physicians' test ordering behavior as a mechanism of this effect. Our analysis reveals that when the queue length is high, physicians respond by over-testing less severe patients in the queue; we document that this “extra” testing generates “extra” post-ED care utilization for these patients. Our findings are based on analysis of a data set assembled from more than four years of microdata from a large U.S. hospital and exhaustive billing data in an integrated health system. Together, this paper contributes new analytical and empirical insights on how physicians' and patients' behavior under ED crowding impacts a previously unstudied system performance measure: post-ED care utilization. Our findings suggest that prior studies estimating the cost of ED crowding provide an underestimate of the true effect, as they do not consider the “extra” post-ED care utilization