This study aims to systematically evaluate the scoring errors made by psychologists in training, in the hopes of providing strong, empirically based guidelines to training programs. Survival analysis was used to determine the number of attempts required for graduate students to achieve proficiency in scoring standardized record forms from the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV). The results suggest that the majority of students will require at least six attempts prior to achieving proficiency in the standardized scoring procedure associated with the WISC-IV. The significant contribution of this study stems from its notably larger sample size (N = 546 record forms) and increased ecological validity compared with previous studies. As a result, this study is likely to improve training in an area that has been established as a core competency for school, clinical, and counselling psychologists.