Keywords: Public reporting, rating system
In the United States, the Scientific Registry of Transplant Recipients publishes public reports on transplant program outcomes. To inform healthcare consumers, programs have been categorized as "as expected," "better than expected," or "worse than expected" based on the outcome of a statistical hypothesis test. The hazard ratio for 1-year posttransplant graft survival is used for posttransplant outcomes. However, the statistical hypothesis test is underpowered for most transplant programs due to relatively small effective sample sizes (e.g., < 10 expected graft failures for most programs). The low power causes poor differentiation of graft survival in the "as expected" group, e.g., a 4-fold difference in hazard ratios. In contrast, the transplant rate ratio is used for pretransplant outcomes and has a 10-fold increase in effective sample size. The higher power causes poor differentiation in the "better than expected" and "worse than expected" groups, e.g., a 5-fold difference in transplant rate ratios. Thus, statistical hypothesis tests fail to group programs with similar performance levels and may fail to inform healthcare consumers of program performance.