CIRANO has published an update of its exploratory study to estimate the incidence of COVID-19 cases in Quebec. This update integrates the data from the second week of collection, which took place from January 20 to 25, 2022, with a sample of 3001 respondents representative of the Quebec population and compares them to the first week of collection.

It should be noted that this study is spread over four consecutive weeks in order to monitor the evolution of the situation. The study uses both a direct sampling strategy and an indirect sampling estimation based on the network scale-up (NSS) method. Details of the methods are available in the CIRANO 2022s-03 working paper.

Highlights: Data collected at time 2 suggest a decrease in the incidence of COVID-19 cases from the previous week. This decrease in incidence is not statistically significant in the direct sampling estimate. However, the decrease is significant in the RPA-based estimates. Therefore, these results should be taken with caution. Nevertheless, by generating smaller standard deviations, the RPA method provides greater precision in estimating the trend in case incidence. We will have to wait for week 3 data to rule on whether this downward trend becomes statistically significant for all our measures.

This study is conducted by a team of researchers composed of David Boisclair (HEC Montréal), Roxane Borgès Da Silva (Université de Montréal and CIRANO), Vincent Boucher (Université Laval) Nathalie de Marcellis-Warin (Polytechnique Montréal and CIRANO), Pierre-Carl Michaud (HEC and CIRANO) and Ingrid Peignier (CIRANO)