A performance assessment consisting of 10 separate exercises was scored with a randomized scoring procedure. All responses to each exercise were rated; then a randomly selected subset of the responses to each exercise received an independent second rating. Each second rating was averaged with the corresponding first rating before the scores were computed. This report presents a method for estimating the scoring reliability coefficient (inter-rater reliability) and the standard error of scoring of the resulting scores. The report concludes with a numerical example.