Cut-off and window are expected to be case specific relating to course of infection and collected data.
Ideally detailed data for the time unit are available (i.e. daily new cases rather than on a weekly or longer basis).
Passive surbeillance and hence biased sampling does not seem to affect the performance on EVI.
Model can be succesful in a variety of cases including syndromic surveillance as an early warning system for upcoming case surge in specific group of cases which can trigger intervention that can be life saving. Such a system would have warned Chinese authorities for a surge, and an upcoming unusual surge in the cases or respiratory ilnesses beyond the season-specifc and region-specific baseline risk at the begininng of the current pandmemic which would have been of atmost importnace.