evidence: There is now strong evidence that wearing masks reduces COVID-19 transmission. While many factors can affect the spread of the virus, preliminary findings show that states and counties with mask mandates are seeing lower transmission than those that have only recommended mask wearing. However, these mandates have incited controversy, and government officials have struggled to determine whether and how to enforce them. [...] "Compliance ambassadors" and education campaigns - States and localities that have resisted mask mandates often state that they prefer "education." However, if education is to be effective, it will require actual investment and action. Charlotte’s enforcement plan uses both enforcement actions and education for businesses, with the latter conducted mostly through environmental health inspectors and part-time ambassadors. Las Vegas has also mobilized 100 "compliance ambassadors." In both cities ambassadors can report violations in businesses, but they do not undertake any enforcement actions themselves. In terms of individual mandates, in DeKalb County, Ga., first-time offenders receive a warning, while second-time offenders can attend a COVID-19 education class instead of receiving a fine. Many states and localities have also implemented public awareness campaigns surrounding masking. While health departments may have limited funds and capacity for evaluation of these campaigns, we encourage data-driven approaches wherever possible. Localities that are able to partner with researchers or private firms can share their results broadly to help inform campaigns throughout the country.