Assessment of surgery residents' operative skills in the operating theater using a modified Objective Structured Assessment of Technical Skills (OSATS): a prospective multicenter study

Surgery. 2014 Nov;156(5):1078-88. doi: 10.1016/j.surg.2014.04.052. Epub 2014 Sep 16.


Background: With the implementation of competency-based curricula, Objective Structured Assessment of Technical Skills (OSATS) increasingly is being used for the assessment of operative skills. Although evidence for its usefulness has been demonstrated in experimental study designs, data supporting OSATS application in the operating room are limited. This study evaluates the validity and reliability of the OSATS instrument to assess the operative skills of surgery residents in the operating theater.

Methods: Twenty-four residents were recruited from seven hospitals within a general surgical training region and classified equally into three groups according to postgraduate training year (PGY). Each resident had to perform five different types of operations. Surgical performance was measured using a modified OSATS consisting of three scales: Global Rating Scale, Overall Performance Scale, and Alphabetic Summary Scale. Validity and reliability metrics included construct validity (Kruskal-Wallis test) and internal consistency reliability (Cronbach's α coefficient). Spearman's correlation coefficients were calculated to determine correlations between the different scales.

Results: Eighteen residents (PGY 1-2 [n = 7]; PGY 3-4 [n = 8]; PGY 5-6 [n = 3]) performed 249 operations. Comparisons of the performance scores revealed that evidence for construct validity depended on the difficulty level of the selected procedures. For individual operations, internal consistency reliability of the Global Rating Scale ranged from 0.93 to 0.95. Scores on the different scales correlated strongly (r = 0.62-0.76, P < .001).

Conclusion: Assessment of operative skills in the operating theater using this modified OSATS instrument has the potential to establish learning curves, allowing adequate monitoring of residents' progress in achieving operative competence. The Alphabetic Summary Scale seems to be of additional value. Use of the Overall Performance Scale should be reconsidered.

Publication types

  • Evaluation Study
  • Multicenter Study
  • Observational Study

MeSH terms

  • Breast Neoplasms / surgery
  • Cholecystectomy, Laparoscopic / standards
  • Clinical Competence*
  • Educational Measurement / methods*
  • General Surgery / education*
  • General Surgery / standards
  • Herniorrhaphy / standards
  • Hip Fractures / surgery
  • Humans
  • Internship and Residency
  • Prospective Studies