Table 2 Variance components of MMI scores for partially crossed naturalistic data from a national assessment centre for selection into GP specialty training
Component and their interaction | Explanation of interactions | Variance component estimate | Proportion of total variance from each factor (%) | Effect sample (degrees of freedom-df) |
|---|---|---|---|---|
Candidate | The consistent differences between candidates’ ability across interviewers and MMI stations | 0.47 | 28% | 1381 |
MMI question | The consistent differences in MMI station difficulty across candidates and interviewers | 0.02 | 1% | 5 |
Interviewer | The consistent differences in interviewer stringency across candidates and interviewers | 0.15 | 9% | 241 |
Interviewer with MMI question | The varying question-specific stringency of interviewers between MMI questions across candidates | 0.06 | 3% | 693 |
Candidate with MMI question | The varying MMI question-specific difficulty between candidates across interviewers | 0.30 | 18% | 6905 |
Candidate with interviewer | The varying views that interviewers have of candidates because of their differing perspectives | 0.67 | 40% | 6905 |