Why Covid-19 restrictions lose effectiveness over time

This study examines how and why the effectiveness of business and social restrictions evolved during the first year of the COVID-19 pandemic, using weekly county-level data from the United States in 2020. Panel data regressions with county-level fixed effects reveal that business restrictions became less effective the longer they remained in place. Residents progressively spent less time at home under sustained restrictions, with this decline accelerating when neighboring counties maintained more lenient policies. The analysis further shows that any initial correlation between policy stringency and COVID-19 fatalities, whether positive or negative, dissipated over time. Estimates indicate this erosion occurred within 20 weeks for many interventions. To explain this declining effectiveness, several hypotheses are tested. The data most strongly support "lockdown fatigue," whereby individuals became progressively less willing to modify their behavior in response to government restrictions over time. This explanation better accounts for the observed patterns than alternative mechanisms, such as improvements in mitigation technology or adaptive behaviors. Point estimates suggest that business restrictions became disassociated from deaths after four to five months, yet many jurisdictions maintained them considerably longer. More broadly, the findings indicate that certain policies were either ineffective from implementation or counterproductive, calling into question their use during the pandemic response.