This study explores associations between performance measures used by Job Corps and estimates of impacts for individual Job Corps centers. The analysis relies on data gathered in 1994-1996 in the course of Mathematica’s National Job Corps Study (NJCS), a rigorous random assignment evaluation of the program, and Job Corps’ contemporaneous administrative data. The NJCS found that Job Corps centers with higher scores on the aggregate performance measure used by the program did not show higher impacts on student outcomes. Extending the analysis in this study, the authors find that even after controlling for student demographic and socioeconomic characteristics, neither the aggregate center performance measure nor its program achievement, placement and quality components can be reliably associated with impacts on student outcomes.