Association between COVID-19 outcomes and mask mandates, adherence, and attitudes
Fig 4
Effect of mask mandates on mask-adherence.
Treatment effect of mask mandates on mask adherence in the only four states (Hawaii, Iowa, North Dakota and New Hampshire) which had late mask mandates (Nov 14, 16, and 20) during the period we have daily state-level mask adherence data. We find that there is a flat pre-treatment trend up to 13 days before the introduction of a mask mandate followed by a 23.4 [12.0,34.8] percentage points increase in mask adherence following introduction (adjusted R2 is 0.925 and p < 0.001).