I use data on cumulative tests, positive tests, and deaths for the coronavirus in South Korea and the U.S. lower-48 states during April 2020 to estimate the extent of infection and the unidentified share of the infected population in each state and in the U.S. as a whole on April 11, 2020. I...

I investigate whether the cross-sectional data on cumulative (symptomatic) cases of coronavirus in the 48 contiguous states of the U.S. at the end of March 2020 provide any evidence that the rate of transmission of the virus declines at higher temperatures. Average temperatures in March varied...

U.S. students in different ethnic groups have very different average scores on the PISA 2012 mathematics and reading tests, with Blacks and Hispanics showing negative gaps relative to White students and Asians showing a positive gap. I investigate whether a student's family characteristics or...

I use data on cumulative tests, positive tests, and deaths for COVID-19 in South Korea and in the lower-48 U.S. states during April and May 2020 to estimate the extent of infection and the unidentified share of the cumulative infected population in each state and in New York City on May 1, 2020....