Estimand

Standard biostatistics/clinical-trials term for the true target quantity a study means to measure, paired against the estimator — the procedure used to measure it. Entered this vault as a cross-domain diagnostic in observation-dca-and-ib-gaps-are-estimand-vs-estimator-stories-resolved-oppositely, applied to ask whether a measured gap between an inferred and a real quantity lives in the target or the tool. First appearance in the vault; watching for recurrence before promoting to a full hub.