Internal structure of mini-CEX scores for internal medicine residents: factor analysis and generalizability.
The mini-CEX is widely used to rate directly observed resident-patient encounters. Although several studies have explored the reliability of mini-CEX scores, the dimensionality of mini-CEX scores is incompletely understood.


OBJECTIVE
explore the dimensionality of mini-CEX scores through factor analysis and generalizability analysis.


METHODS
factor analytic and generalizability study using retrospective data.


METHODS
eighty five physician preceptors and 264 internal medicine residents (postgraduate years 1-3).


METHODS
preceptors used the six-item mini-CEX to rate directly observed resident-patient encounters in internal medicine resident continuity clinics. We analyzed mini-CEX scores accrued over 4 years using repeated measures analysis of variance to generate a correlation matrix adjusted for multiple observations on individual residents, and then performed factor analysis on this adjusted correlation matrix. We also performed generalizability analyses.


RESULTS
eighty-five preceptors rated 264 residents in 1,414 resident-patient encounters. Common factor analysis of these scores after adjustment for repeated measures revealed a single-factor solution. Cronbach's alpha for this single factor (i.e. all six mini-CEX items) was ≥ 0.86. Sensitivity analyses using principal components and other method variations revealed a similar factor structure. Generalizability studies revealed a reproducibility coefficient of 0.23 (0.70 for 10 raters or encounters).


CONCLUSIONS
the mini-CEX appears to measure a single global dimension of clinical competence. If educators desire to measure discrete clinical skills, alternative assessment methods may be required. Our approach to factor analysis overcomes the limitation of repeated observations on subjects without discarding data, and may be useful to other researchers attempting factor analysis of datasets in which individuals contribute multiple observations.
Division of General Internal Medicine and Office of Education Research, Mayo Clinic College of Medicine, Baldwin 4-A, 200 First Street SW, Rochester, MN 55905, USA. cook.david33@mayo.edu
David A
DA
Cook
Thomas J
TJ
Beckman
Jayawant N
JN
Mandrekar
V Shane
VS
Pankratz
D000704:Analysis of Variance; D002983:Clinical Competence / Q000706:statistics & numerical data*; D016001:Confidence Intervals; D004521:Educational Measurement / Q000379:methods* / Q000706:statistics & numerical data; D004522:Educational Status; D005163:Factor Analysis, Statistical; D006801:Humans; D007388:Internal Medicine / Q000193:education*; D007396:Internship and Residency / Q000706:statistics & numerical data*; D011231:Preceptorship; D011594:Psychometrics; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013223:Statistics as Topic; D014481:United States