  Due to delay in reporting, the daily national and statewide COVID-19
incidence counts are often unreliable and need to be estimated from recent
data. This process is known in economics as nowcasting. We describe in this
paper a simple random forest statistical model for nowcasting the COVID - 19
daily new infection counts based on historic data along with a set of simple
covariates, such as the currently reported infection counts, day of the week,
and time since first reporting. We apply the model to adjust the daily
infection counts in Ohio, and show that the predictions from this simple
data-driven method compare favorably both in quality and computational burden
to those obtained from the state-of-the-art hierarchical Bayesian model
employing a complex statistical algorithm.
