The effective reproduction number (Rt) estimates the average number of secondary cases generated by an individual with SARS-CoV-2. If Rt is above 1, the number of daily new infections will grow at an exponential rate. If it is below 1, the number of daily new infections will decrease. If field {ABOVE1=1}, then the transmission rate for that day did not meet the Reopening DC metric. The effective reproduction number must remain below 1 for a consecutive 5 days in order to achieve Reopening DC. The reproduction number is calculated in retrospect - data reported today is used to calculate the Rt for 14 days ago. This allows time for reported cases on a day to be more complete (~75% of cases reported), and calculates Rt over a 7−day window. Rt is primarily affected by 1) under-reporting rate over time, 2) caseload by start of infectious period, and 3) the serial interval (average between the start of the infectious period in one individual, and the start of the infectious period in an individual they infect). Rt is estimated from cases by start of infectious period using the EpiEstim algorithm, and the day plotted is the midpoint of the 7 day window. Rt may not be a reliable indicator of transmission as cases decline, as it becomes more uncertain with less data, and can be heavily impacted by disease events in other states which are imported into DC. For this reason, Rt is not measured at geographies below the city level. This data is used to calculate the Reopening DC metric where the effective reproduction number must be below 1 for 5 days. Data are subject to change on a daily basis and reported at a 12-day lag for proper analysis.