Calibration
CritPt → GPQA Diamond
GPQA Diamond is estimated from CritPt with a Michaelis–Menten + offset curve fitted on 44 models measured on both: y = 0.7494 + 0.2031·x / (0.02860 + x), R² = 0.74, cross-validated error 2.9 pp. It is used for 0 estimates.