Understanding the Effects of Tennessee's Open Covid-19 Testing Policy: Bounding Policy Effects with Nonrandomly Missing Data

Callaway, Brantly; Li, Tong

Increased testing for Covid-19 is seen as one of the most important steps to be implemented to re-open the economy. The current paper considers Tennessee's ``open-testing'' policy where the state substantially increased the number of available tests while opening testing to all individuals that wanted a test; this is unlike most other states that have required that individuals must be showing specific symptoms in order to be tested. In the current paper, we examine whether Tennessee's policy has affected (i) the number of confirmed Covid-19 cases, (ii) the number of trips to work, and (iii) the (unobserved) number of actual Covid-19 cases. To study these effects, we employ standard identifying assumptions in the policy evaluation literature, but this strategy is greatly complicated by the non-random nature of the tests. We construct bounds on the policy effects of interest. We find suggestive evidence that Tennessee's open-testing policy has led to a reduction in the number of confirmed and total cases as well as reduced travel in counties that have experienced relatively large increases in confirmed cases.