PORTRAIT: a calibrated patient Passport with built-in refusal - describing individuals against a reference population

Background Averagebased summaries serve individual patients poorly PORTRAIT is a calibrated abstentionaware tool that describes where one patient sits relative to a reference population across 12 cardiometabolic markers how confident that placement is and which features drive it PORTRAIT describes it does not diagnose or predict Abstention is a designed feature given the known limits of conditional coverage Methods Conformal calibration was combined with distributionfree coverage bounds quantileregression coordinates and copulabased joint structure A frozen reference cohort n9421 supplied fixed calibration a heldout cohort n2247 tested transportability across six strata A release gate required the minimum perslice coverage to hold across 4 of 5 seeds Coverage was retested under survey weighting to the US adult population Coherence was reported as a descriptive joint coordinate Discrimination was summarised with Harrells C and multiplicity controlled by BHFDR Interface conformance was assessed against defined requirements Nielsen heuristics and WCAG 22 AA with attention to automation bias and riskgraph design Results The frozen reference held all six strata within band 08640903 at abstention 0113 whereas a resplit undercovered to 071 at abstention 0227 coverage survived survey weighting The release gate passed on 4 of 5 seeds at abstention 0101 against a nominal 090 and in the frozenreference configuration that ships all six strata held inside the calibrated band 08640903 Coherence showed orthogonality 0444 to raw extremity and correlated 0892 with a copulaMahalanobis distance while remaining deliberately nonidentical so it adds perfeature information Two transfer tests returned negatives the ocular transfer did not hold coverage at thinn Adding coherence changed mortality discrimination by deltaC 00047 Interface requirements moved from 142718 to 38147 METPARTIALUNMET Nielsen severity resolved 7 of 10 issues WCAG 22 AA text criteria passed Conclusions PORTRAIT situates a patient against a frozen reference holds coverage under survey weighting to the US adult population and abstains when calibration cannot be supported The headline result is that the frozen reference held coverage where a resplit did not