This plot shows the reported or estimated case rates over time for each state. Each estimate is calculated as described in this working paper, and is based on the 7-day average of daily positivity rate (# positives / # tests). To generate estimates, the authors assume that states test residents when symptoms are present. In a few states where testing procedures vary (for example testing is available regardless of symptoms), estimated cases may appear lower than reported cases. In DC, for example, estimated cases are lower than reported cases due to frequent testing for government officials and workers—many of whom do not live in DC—regardless of symptom presentation. See the paper for more information.