We evaluate the impacts of implementing and lifting nonpharmaceutical interventions (NPIs) in US counties on the daily growth rate of COVID-19 cases and compliance, measured through the percentage of devices staying home, and evaluate whether introducing and lifting NPIs protecting selective populations is an effective strategy. We use difference-in-differences methods, leveraging on daily county-level data and exploit the staggered introduction and lifting of policies across counties over time. We also assess heterogenous impacts due to counties’ population characteristics, namely ethnicity and household income. Results show that introducing NPIs led to a reduction in cases through the percentage of devices staying home. When counties lifted NPIs, they benefited from reduced mobility outside of the home during the lockdown, but only for a short period. In the long term, counties experienced diminished health and mobility gains accrued from previously implemented policies. Notably, we find heterogenous impacts due to population characteristics implying that measures can mitigate the disproportionate burden of COVID-19 on marginalized populations and find that selectively targeting populations may not be effective.

我们评估了在美国各县实施和取消非药物干预措施 (NPI) 对 COVID-19 病例日增长率和合规性的影响（通过留在家里的设备百分比来衡量），并评估引入和取消保护特定人群的 NPI 是否是一种有效的措施。有效的策略。我们使用双重差分法，利用每日县级数据，并利用随着时间的推移，各县政策的交错出台和取消。我们还评估了各县人口特征（即种族和家庭收入）造成的异质影响。结果表明，引入 NPI 可以通过留在家里的设备百分比来减少病例。当各县取消 NPI 时，他们会因封锁期间外出活动减少而受益，但这只持续很短一段时间。从长远来看，各县从之前实施的政策中获得的健康和流动性收益有所减少。值得注意的是，我们发现由于人口特征而产生异质性影响，这意味着采取措施可以减轻 COVID-19 对边缘化人群造成的不成比例的负担，并发现选择性针对人群可能不会有效。