A database integrating 90 years of empirical studies reporting intercorrelations among rated job performance dimensions was used to test the hypothesis of a general factor in job performance. After controlling for halo error and 3 other sources of measurement error, there remained a general factor in job performance ratings at the construct level accounting for 60% of total variance. Construct-level correlations among rated dimensions of job performance were substantially inflated by halo for both supervisory (33%) and peer (63%) intrarater correlations. These findings have important implications for the measurement of job performance and for theories of job performance.