The New York City Transit Authority (MTA) releases weekly data on the number of entries and exits at each of its subway stations. This analysis is based on the data retrieved from the following weeks Week of January 19 - “normal week” before the outbreak, used as a control Week of March 8 - week before NYC placed various restrictions Week of March 15 What data is being analysed? The data is based on entries into the specified stations, during the timeframe noted.