Designing Dynamic Reassignment Mechanisms: Evidence from GP Allocation

We study the problem of designing a dynamic reassignment mechanism when agents' preferences over objects change over time. In the context of Norway's system for (re)assigning patients to general practitioners (GPs), we provide direct evidence of misallocation under the current mechanism—patients waiting for each others' GPs, but who cannot trade—and estimate a structural model of GP-switching behavior to evaluate alternatives. Introducing top trading cycles (TTC) would, on average, reduce waiting times and increase patient welfare. However, patients endowed with less desirable GPs would be harmed. Prioritizing these patients can avoid these harms while preserving most of the gains from TTC.