Test Sensitivity for Infection versus Infectiousness of SARS-CoV-2

19 Pages Posted: 31 Aug 2020 Last revised: 27 Nov 2020

See all articles by Joshua S. Gans

Joshua S. Gans

University of Toronto - Rotman School of Management; NBER

Multiple version iconThere are 2 versions of this paper

Date Written: November 25, 2020


The most commonly used test for the presence of SARS-CoV-2 is a PCR test that is able to detect very low viral loads and inform on treatment decisions. Medical research has confirmed that many individuals might be infected with SARS-CoV-2 but not infectious. Knowing whether an individual is infectious is the critical piece of information for a decision to isolate an individual or not. This paper examines the value of different tests from an information-theoretic approach and shows that applying treatment-based approval standards for tests for infection will lower the value of those tests and likely causes decisions based on them to have too many false positives (i.e., individuals isolated who are not infectious). The conclusion is that test scoring be tailored to the decision being made.

Note: Funding: I have received no funding for this research.

Conflict of Interest: No conflicts of interest.

Keywords: COVID-19, testing, information value, infectiousness

JEL Classification: I18

Suggested Citation

Gans, Joshua S., Test Sensitivity for Infection versus Infectiousness of SARS-CoV-2 (November 25, 2020). Available at SSRN: https://ssrn.com/abstract=3682242 or http://dx.doi.org/10.2139/ssrn.3682242

Joshua S. Gans (Contact Author)

University of Toronto - Rotman School of Management ( email )


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