Table 7. Construct validity analysis: Pearson's correlation coefficient between SF-36 questionnaire scales and Work Productivity and Activity Impairment-General Health (WPAI-GH) questionnaire scales.

			WPAI-GH scales
SF-36 Scales	Work time missed (%)	Impairment at work (%)	Overall work productivity loss (%)	Activity impairment (%)
Physical functioning
Pearson's correlation	-0.079	-0.371	-0.352	-0.367
p-value	0.435	0.000*	0.000*	0.000*
Role limitations due to physical health
Pearson's correlation	-0.035	-0.358	-0.315	-0.435
p-value	0.727	0.000*	0.000*	0.000*
Bodily pain
Pearson's correlation	-0.055	-0.472	-0.445	-0.420
p-value	0.587	0.000*	0.000*	0.000*
General health perceptions
Pearson's correlation	-0.052	-0.224	-0.200	-0.198
p-value	0.608	0.025†	0.046†	0.049†
Vitality
Pearson's correlation	-0.067	-0.310	-0.264	-0.327
p-value	0.510	0.002‡	0.008‡	0.000*
Social functioning
Pearson's correlation	-0.095	-0.406	-0.377	-0.243
p-value	0.348	0.000*	0.000*	0.015†
Role limitations due to emotional health
Pearson's correlation	-0.109	-0.206	-0.181	-0.170
p-value	0.278	0.040†	0.072	0.091
General mental health
Pearson's correlation	-0.174	-0.343	-0.317	-0.172
p-value	0.084	0.000*	0.000*	0.086

^* = p < 0.001;

^† = p < 0.05;

^‡ = p < 0.01.