Fixed-time descriptive statistics underestimate extremes of epidemic curve ensembles (and how to fix it?)
Jonas Juul (Center for Applied Mathematics, Cornell University)
Across the world, scholars are racing to predict the spread of the novel coronavirus, COVID-19. Such predictions are often pursued by numerically simulating epidemics with a large number of plausible combinations of relevant parameters. It is essential that any forecast of the epidemic trajectory derived from the resulting ensemble of simulated curves is presented with confidence intervals that communicate the uncertainty associated with the forecast. Here we argue that the state-of-the-art approach for summarizing ensemble statistics does not capture crucial epidemiological information. In particular, the current approach systematically suppresses information about the projected trajectory peaks. The fundamental problem is that each time step is treated separately in the statistical analysis. As one possible solution, we suggest using curve-based descriptive statistics to summarize trajectory ensembles. We suspect that participants in the SCAN seminar might know how the proposed methods could be improved and we would greatly appreciate any such suggestions.