Table 1

Summary of the five different model structures that were considered

	Time dependency of ARAT alone	Covariate: all main effects	Covariate: all interaction effects (with time)	Covariate: only significant main effects	Covariate: only significant interaction effects (with time)	Covariate: only shoulder abduction and finger extension and interaction (with time)
Model 1 (most extensive model)	X	X	X
Model 2 (all covariates, all main effects, only the significant interactions with time)	X	X			X
Model 3 (only significant main effects and significant interactions with time)	X			X	X
Model 4 (SAFE model)	X					X
Model 5 (minimal model)	X

For further description of the models, see prediction model development in the methods. The safe model was used as the final model for cross-validation.
ARAT, Action Research Arm Test; SAFE, Shoulder-Abduction-Finger Extension model.