“Contribution 1: Misplaced Focus on Precision for Decision Making
[..] In 2021, skepticism about cost, uptake, and sensitivity made it hard to get home antigen tests for SARS-CoV-2 into Americans’ hands. Rather than try to resolve those uncertainties, we built a model that was deliberately hostile to testing: 75% of tests discarded, 75% of positive results ignored, a third of isolating persons quitting daily, 80% sensitivity, and $5 cost. Even with every parameter stacked against the intervention, we found that mass distribution could avert hundreds of thousands of infections at a defensible cost.
Rather than win arguments about the uncertainties, we needed only to show that the policy decision did not hinge on them. The value of perfect information about the uncertain parameters was 0. Sometimes, claiming that “more research is needed” is careful science; sometimes, it is just delay.
Contribution 2: Portable Truths About Complex Systems
[..] The cost-effectiveness of a screening test is really the cost-effectiveness of the lifetime of expensive treatment that it sets in motion. If the test is cheap relative to the downstream care pathway, its price and the prevalence of the condition screened for barely affect the total. That insight—which travels to cancer screening, addiction treatment, and other care “cascades”—reframed the conversation: We stopped arguing whether we could afford to test more people and started asking whether we had the infrastructure to care for those who tested positive.
A second example: Our analysis of COVID-19 reopening strategies for college campuses (7) found that testing frequency mattered more than accuracy. Amid public focus on the supposed inadequacy of cheap antigen tests relative to polymerase chain reaction, our spreadsheet-based model showed that, in most scenarios, a cheaper, less accurate test deployed twice a week beat a more accurate test deployed every 2 weeks. That insight reflected a fundamental system property: The value of surveillance comes primarily from interrupting transmission chains before they grow, which requires speed and frequency.”
Full article, AD Paltiel, Annals of Internal Medicine, 2026.10.13