Identifying the Bottleneck Unit: Impact of Congestion Spillover in Hospital Inpatient Unit Network
33 Pages Posted: 18 Sep 2020 Last revised: 4 Aug 2021
Date Written: August 3, 2021
Because a hospital is an interconnected, interdependent network of care units, allocating resources--beds, nurses, and improvement initiatives--to one unit to reduce its congestion and improve its performance may have spillover effects on other units. As such, to identify the bottleneck unit and improve access to care, hospital administrators need to take into account potential effects of congestion spillover. We use detailed patient data from a hospital collected over five years to empirically examine whether and how much congestion propagates through the network of inpatient units and identify the bottleneck unit. Our estimation result suggests that the magnitude of the congestion spillover is substantial. For example, increasing one inpatient unit's utilization by 10 percentage points today can increase its neighboring inpatient unit's utilization by up to 5.71 percentage points tomorrow. Using counterfactual analyses, we estimate the effect of adding a bed to each unit. We find that adding a bed to the bottleneck unit can free up 3.75 beds in the hospital, which can be translated to 347.40 more hospital visits per year or a 3% increase in hospital throughput. This effect is about three times bigger in magnitude compared to what one can achieve by naively choosing which hospital unit to add a bed to. Hospitals and other manufacturing and service systems with complex interdependence across resources can use our empirical framework to examine the spillover effect of resources on performance metrics and leverage such understanding to effectively improve their operations.
Keywords: empirical operations management, network effect, bottleneck, congestion, healthcare, inpatient unit
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