Emergency-department data are a window, not a census

ED data are especially valuable for timely surveillance of health-care use and syndromic signals. They do not automatically estimate population incidence because the pathway into emergency care is selective and can change over time. Weavidence Insights. Independent scholarly publication; not externally peer reviewed. AI-assisted drafting and editorial development were used. Pietro Corona remains responsible for the final published claims, source selection, interpretation and approval.