Table 4.

Scoring coefficients for the physical and mental health summary scores from the CFA model (scoring coefficients found by Hays et al. [15] in parentheses)

Domain	Physical health summary score	Mental health summary score
Physical function	1.546 (0.872)	− 0.073 (− 0.015)
Paina	0.030 (− 0.094)	− 0.122 (− 0.154)
Ability to participate in social roles and activities	− 0.011 (0.113)	0.361 (0.252)
Fatigue	0.008 (− 0.009)	− 0.417 (− 0.351)
Emotional distressb	− 0.002 (0.003)	− 0.362 (− 0.257)
Sleep disturbance	− 0.001 (0.002)	− 0.221 (− 0.139)

Scoring coefficients can be used to calculate physical and mental health summary scores. Taking the Physical Health Summary (PHS) score as an example: PHS_z = (physical function z-score*1.546) + (pain z-score *0.030) + (ability to participate z-score*-0.011) + (fatigue z-score*0.008) + (sleep disturbance z-score*-0.002) + (emotional distress z = score*-0.001); PHS = PHS_Z*10 + 50

^aPain is average of pain interference and pain intensity item

^bEmotional distress is average of anxiety and depression