The rigors of standardized testing make for numerous opportunities for examiner error, including simple computational mistakes in scoring. Although experts recommend that test scoring be double-checked, the extent to which independent double-checking would reduce scoring errors is not known. A double-checking procedure was established at a psychology training clinic in an effort to improve intelligence test scoring accuracy. The authors examined 50 archival protocols to determine the effects of independent double-checking on Wechsler Intelligence Scale for Children-Third Edition scores. As expected, these procedures significantly changed IQ scores, increasing their accuracy. Anonymous trainee feedback supported the utility of these efforts and endorsed it as making a useful contribution to professional development. Recommendations for instituting such procedures in training settings are discussed, and a sample checklist to guide double-checking is provided. (Contains 1 table.)