In virtually every U.S. state, large-scale social distancing came before stay-at-home orders. There’s simply no evidence that Americans resisted social distancing until ordered to comply. Instead, the evidence suggests that Americans were voluntarily social distancing up until the date when they received shelter in place orders. Nor is this effect driven by other policies. The figures below show the same data, arranged by the date on which assemblies of over fifty were banned, the date on which assemblies of over 500 were banned, the date on which public school was canceled, the date on which restaurants were closed, and the date on which entertainment facilities were closed. Across all of these policies, social distancing very clearly began before the policy was implemented.
None of the state-level policies identified appears to be responsible for social distancing. However, it turns out that there’s no need to get so complicated. Almost every state’s social distancing turns out to have begun at almost the exact same time: March 8–13, with March 11 being the major inflection point. Put bluntly, March 11 is the date on which America began socially distancing. Before March 11, essentially only Washington State—and to a much smaller extent California—were socially distancing. This is no surprise, since Governor Inslee declared a state of emergency in Washington on February 29, and California counties had begun declaring local health emergencies as early as February 10. Where emergencies were declared early, social distancing began earlier as well.