“…1 Consequently, to aid hospital enterprises in reducing HFR, hundreds of studies have used or developed indices and models to predict HFR, 30-day all-cause or otherwise. [2][3][4] These HFR studies have varied greatly in their readmission time frames (30d -1yr) and methodologies (risk indices, statistical models, machine learning), as well as in the data underpinning their predictions (clinical, administrative, psychosocial). [4][5][6][7][8] However, the degrees of performance and applicability needed to make transformative progress in predicting HFR have been notoriously difficult to achieve 4,9 , begging the question of why.…”