Appendix 3.

Summary Measures of Model Fit for Random Forest Models

Metric	Model fit for prediction of COPCs
	TMD	Headache	IBS	LBP	Fibromyalgia
Observed cases, %	0.278	0.412	0.241	0.212	0.079
Area under precision-recall curve	0.599	0.624	0.404	0.512	0.329
Area under receiver operator characteristic curve	0.783	0.701	0.704	0.777	0.786
Brier score	0.173	0.215	0.193	0.163	0.134
Mutual information index	0.064	0.036	0.023	0.071	0.046
Proportion of variance explained	0.202	0.137	0.129	0.198	0.158
Maximum variable importance factor: Predicting cases	0.297	0.089	0.134	0.236	0.269
Maximum variable importance factor: Predicting controls	0.006	0.014	0.005	0.005	0.008
Maximum variable importance factor: All	0.007	0.016	0.003	0.015	0.003