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Table 3 Variance component estimates and generalizability coefficients for the 2-facet model (persons, stations) using a minimum norm quadratic unbiased estimation (MINQUE) approach

From: Applying generalized theory to optimize the quality of high-stakes objective structured clinical examinations for undergraduate medical students: experience from the French medical school

Variance component estimates *

Source of variation

Clinical skills score**

% variance

Generic skills score**

% variance

Global performance

Percentage of variance

Person (n = 73)

32.228

8.15

46.183

14.33

0.121

13.75

Station (n = 3)

95.582

24.17

11.505

3.57

0.125

14.20

Person x Station

108.898

27.54

137.725

42.71

0.312

35.45

Residual error

158.743

40.14

127.014

39.39

0.322

36.59

G-coefficient**

0.503

 

0.923

 

0.742

 
  1. *Variance component estimates for persons (P = student or object of measurement); stations (S), examiners (E), interactions between facets and residual error (e) reflecting unidentified sources of error
  2. **expressed as a percentage
  3. ***G-coefficients of students’ scores were calculated via the following equation:
  4. Person/[Person + (Station/3) + (Person × Station/219)]