CJV has a higher rank probability than total SNR after four selected counterfactual grade changes in 288 MR-ART motion scans.

In 8,000 eligible scan pairs from 288 motion scans in the MR-ART dataset, total SNR had a higher rank probability than CJV (0.851000 vs 0.826750). An exact finite-table analysis found that four selected grade changes between grades 2 and 3 are the minimum needed to reverse that order; no set of three or fewer permitted changes does so. Two within-instruction exchanges (four labels changed) also reverse the order while keeping grade counts fixed. These are counterfactual labels, not new expert observations or estimates of label error. The result applies only to the analyzed tables and rules. It does not establish a population order, error rate, or clinical effect.

MR-ART · magnetic resonance imaging · image quality · expert grades · rank probability · sensitivity analysis · counterfactual labels