Establishing cutoff scores on assessments of surgical skills to determine surgical competence.

OBJECTIVE: The aim of this study was to establish minimum cutoff scores on intraoperative assessments of surgical skills to determine surgical competence for vaginal hysterectomy. STUDY DESIGN: Two surgical rating scales, the Global Rating Scale of Operative Performance and the Vaginal Surgical Skills Index, were used to evaluate trainees while performing vaginal hysterectomy. Cutoff scores were determined using the Modified Angoff method. RESULTS: Two hundred twelve evaluations were analyzed on 76 surgeries performed by 27 trainees. Trainees were considered minimally competent to perform vaginal hysterectomy if total absolute scores (95% confidence interval) on Global Rating Scale = 18 (16.5-20.3) and Vaginal Surgical Skills Index = 32 (27.7-35.5). On average, trainees met new cutoffs after performing 21 and 27 vaginal hysterectomies, respectively. With the new cutoffs applied to the same cohort of fourth-year obstetrics and gynecology trainees, all residents achieved competency in performing vaginal hysterectomy by the end of their gynecology rotations. CONCLUSION: Standard-setting methods using cutoff scores may be used to establish competence in vaginal surgery.