OBJECTIVES: The aims of the study were to develop and gather validity evidence for a feasible rating scale for formative and summative assessment of total laparoscopic hysterectomy in the operating theatre.

STUDY DESIGN: The study was a prospective observer-blinded cohort study. The rating scale was developed according to the generic format of Objective Structured Assessment of Technical Skills. We applied the contemporary framework of validity to examine validity evidence of the content, response process, internal structure, relationship to other variables, and consequences. Two experienced gynecologists constructed a preliminary version of the rating scale, which was reviewed by a multicentre team of experienced gynecologists in a modified Delphi process. The surgeons (beginners and experienced surgeons) were video recorded during live performance of total laparoscopic hysterectomies. Two blinded raters evaluated the performances independently using the rating scale. Internal consistency reliability and interrater reliability were calculated as measures of internal structure. The performances of the two groups were compared and a pass/fail score was set to show the consequences of the rating scale.

RESULTS: The content of the rating scale was defined during three Delphi rounds and upon agreement comprised of 12 items. Sixteen participants including 8 beginners and 8 experienced surgeons performed total laparoscopic hysterectomies. The internal consistency reliability of the items was 0.95 (Cronbach's alpha), and the interrater reliabilities (Intraclass Correlation Coefficient, absolute agreement) were 0.996 for one rater and 0.998 for two raters (P <  0.001 for all correlations). The beginners' mean performance score was 19.2 (SD 7.1) and the experienced surgeons' score was 36.4 (SD 3.9); the groups performed statistically significantly different (P <  0.001). The pass/fail score was 29.3 with no false positives and no false negatives.

CONCLUSION: With this study, a feasible rating scale for the objective assessment of total laparoscopic hysterectomy was developed with sound validity evidence. The rating scale is suitable for both formative and summative feedback in the commencement of surgical training in gynecology.