Table 2.

Internal validation of mapping algorithms

	All patients	Patients with HAQ less than 1	Patients with HAQ between 1 and 2	Patients with HAQ greater than 2
Models with HAQ covariate only
RMSE (SD)
MV probit	0.196 (0.013)	0.065 (0.003)	0.300 (0.019)	0.293 (0.039)
Beta	0.246 (0.021)	0.094 (0.018)	0.376 (0.037)	0.343 (0.011)
Samples where RMSE was lower in the MV probit (%)	100	99.6	99.8	91.8
Models with HAQ and VAS pain covariates
RMSE (SD)
MV probit	0.177 (0.022)	0.088 (0.022)	0.226 (0.027)	0.277 (0.031)
Beta	0.196 (0.016)	0.099 (0.014)	0.261 (0.028)	0.281 (0.014)
Samples where RMSE was lower in the MV probit (%)	94.2	90.8	95.2	63.8