An Empirical Investigation Into Milestones Factor Structure Using National Data Derived From Clinical Competency Committees.

PURPOSE To investigate whether milestone data obtained from clinical competency committee (CCC) ratings in a single specialty reflected the 6 general competency domains framework. METHOD The authors examined milestone ratings from all 275 U.S. Accreditation Council for Graduate Medical Education-accredited categorical obstetrics and gynecology (OBGYN) programs from July 1, 2018, to June 30, 2019. The sample size ranged from 1,371 to 1,438 residents from 275 programs across 4 postgraduate years (PGYs), each with 2 assessment periods. The OBGYN milestones reporting form consisted of 28 subcompetencies under the 6 general competency domains. Milestone ratings were determined by each program's CCC. Intraclass correlations (ICCs) and design effects were calculated for each subcompetency by PGY and assessment period. A multilevel confirmatory factor analysis (CFA) perspective was used, and the pooled within-program covariance matrix was obtained to compare the fit of the 6-domain factor model against 3 other plausible models. RESULTS Milestone ratings from 5,618 OBGYN residents were examined. Moderate to high ICCs and design effects greater than 2.0 were prevalent among all subcompetencies for both assessment periods, warranting the use of the multilevel approach in applying CFA to the milestone data. The theory-aided split-patient care (PC) factor model, which used the 6 general competency domains but also included 3 factors within the PC domain (obstetric technical skills, gynecology technical skills, and ambulatory care), was consistently shown as the best-fitting model across all PGY by assessment period conditions, except for one. CONCLUSIONS The findings indicate that in addition to using the 6 general competency domains framework in their rating process, CCCs may have further distinguished the PC competency domain into 3 meaningful factors. This study provides internal structure validity evidence for the milestones within a single specialty and may shed light on CCCs' understanding of the distinctive content embedded within the milestones.