The Metropolitan Transportation Authority (MTA, New York City’s public transportation provider), provides observational data on mask wearing compliance. This could be an interesting data source for researchers working on Covid and social interactions in public spaces (see, for instance, this paper and this paper by Marie Lindegaard, Wim Bernasco, and colleagues). Among other possibilities, the data could serve as a point of comparison for the performance of a computer vision algorithm that identifies computationally compliance with mask wearing in public spaces. This could be an interesting opportunity to further develop computer vision as a method in video-based research and in the social sciences more broadly.