Estimates of the Undetected Rate among the SARS-CoV-2 Infected using Testing Data from Iceland

James H Stock; Karl M Aspelund; Michael Droste; Christopher D Walker

Both the eligibility window method (Equation (1) and the odds ratio method (Equation (2)) require an estimate of NI f , the fraction of infections among the NUHI-ineligible. If the deCODE sample were a random sample of the NUHI-ineligible population, this would be estimated by the NUHI positive testing rate. However, the deCODE sample has two complications: it was voluntary, and those in quarantine were excluded. The next two sections discuss these issues turn, and show how the deCODE positive testing rate can be used to bound NI f that accounts for the complications in the deCODE testing sample. For the eligibility window method, we thereby estimate a lower bound (a conservative estimate of θ), and for the odds ratio method we are able to estimate both a lower and upper bound.