The SAM Approach to Epidemic Models

We discuss the connections between epidemiology models and the search and matching (SAM) approach and draw conclusions about modeling the trade-offs between lockdowns and disease spread. We review the pre-COVID epidemics literature, which was mainly by epidemiologists, and the post-COVID surge in economics papers that use meeting technologies to model the trade-offs. We argue that modeling the decentralized equilibrium with economic trade-offs gives rise to substantially different results from the earlier epidemics literature, but policy action is still welfare-improving because of several externalities.