Deriving an overall appearance domain score by applying bifactor IRT analysis to the BODY-Q appearance scales
Bibliographic record
Abstract
PURPOSE: With the BODY-Q, one can assess outcomes, such as satisfaction with appearance, in weight loss and body contouring patients using multiple scales. All scales can be used independently in any given combination or order. Currently, the BODY-Q cannot provide overall appearance scores across scales that measure a similar super-ordinate construct (i.e., overall appearance), which could improve the scales' usefulness as a benchmarking tool and improve the comprehensibility of patient feedback. We explored the possibility of establishing overall appearance scores, by applying a bifactor model to the BODY-Q appearance scales. METHODS: In a bifactor model, questionnaire items load onto both a primary specific factors and a general factor, such as satisfaction with appearance. The international BODY-Q validation patient sample (n = 734) was used to fit a bifactor model to the appearance domain. Factor loadings, fit indices, and correlation between bifactor appearance domain and satisfaction with body scale were assessed. RESULTS: All items loaded on the general factor of their corresponding domain. In the appearance domain, all items demonstrated adequate item fit to the model. All scales had satisfactory fit to the bifactor model (RMSEA 0.045, CFI 0.969, and TLI 0.964). The correlation between the appearance domain summary scores and satisfaction with body scale scores was found to be 0.77. DISCUSSION: We successfully applied a bifactor model to BODY-Q data with good item and model fit indices. With this method, we were able to produce reliable overall appearance scores which may improve the interpretability of the BODY-Q while increasing flexibility.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.029 | 0.057 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.004 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".