Table 6 Item discrimination, difficulty, and average amount of information in item response theory

Physical functioning (PF)

PF01

2.73 (0.01)

 − 1.43 (0.01)

1.02

0.21 (0.01)

PF02

2.73 (0.01)

 − 2.53 (0.05)

0.74

2.20 (0.03)

 − 3.13 (0.05)

0.45

 − 1.07 (0.01)

 − 1.40 (0.02)

PF03

2.73 (0.01)

 − 2.55 (0.05)

0.73

 − 1.14 (0.01)

PF04

2.73 (0.01)

 − 2.05 (0.03)

0.9

2.20 (0.03)

 − 2.60 (0.04)

0.54

 − 0.87 (0.01)

 − 1.17 (0.01)

PF05

2.73 (0.01)

 − 2.45 (0.04)

0.65

 − 1.54 (0.02)

PF06

2.73 (0.01)

 − 1.88 (0.02)

0.89

 − 0.90 (0.01)

PF07

2.73 (0.01)

 − 1.42 (0.01)

0.95

 − 0.25 (0.01)

PF08

2.73 (0.01)

 − 1.96 (0.03)

0.89

 − 0.92 (0.01)

PF09

2.73 (0.01)

 − 2.51 (0.05)

0.63

 − 1.58 (0.02)

PF10

2.73 (0.01)

 − 1.69 (0.02)

0.74

 − 1.20 (0.01)

Role physical (RP)

RP1

2.17 (0.02)

0.77 (0.01)

0.43

RP2

2.17 (0.02)

0.53 (0.01)

0.43

2.32 (0.03)

0.52 (0.01)

0.46

RP3

2.17 (0.02)

0.65 (0.01)

0.43

2.32 (0.03)

0.63 (0.01)

0.46

RP4

2.17 (0.02)

0.52 (0.01)

0.43

Bodily pain (BP)

BP1

0.45 (0.01)

 − 10.26 (0.48)

0.06

 − 8.08 (0.31)

 − 4.60 (0.16)

 − 1.33 (0.06)

1.24 (0.06)

BP2

0.45 (0.01)

0.32 (0.05)

0.05

1.06 (0.02)

0.18 (0.02)

0.24

4.65 (0.17)

2.40 (0.04)

7.46 (0.28)

3.83 (0.07)

10.00 (0.44)

5.28 (0.12)

General health (GH)

GH1

1.76 (0.01)

 − 3.05 (0.05)

0.76

0.91 (0.01)

 − 1.80 (0.03)

0.24

 − 1.11 (0.02)

0.21 (0.02)

 − 0.13 (0.01)

1.72 (0.03)

1.2 (0.01)

4.93 (0.09)

GH2

1.76 (0.01)

 − 2.33 (0.03)

0.73

 − 1.46 (0.02)

 − 0.23 (0.01)

0.54 (0.01)

GH3

1.76 (0.01)

 − 2.77 (0.03)

0.68

 − 2.14 (0.02)

 − 0.89 (0.01)

0.35 (0.01)

GH4

1.76 (0.01)

 − 2.43 (0.03)

0.67

 − 1.55 (0.02)

 − 0.52 (0.01)

0.17 (0.01)

GH5

1.76 (0.01)

 − 2.75 (0.03)

0.71

 − 2.04 (0.02)

 − 0.78 (0.01)

0.57 (0.01)

Vitality (VT)

VT1

0.74 (0.00)

 − 2.43 (0.04)

0.17

0.29 (0.03)

1.68 (0.03)

3.33 (0.05)

4.71 (0.07)

VT2

0.74 (0.00)

 − 2.74 (0.04)

0.17

0.91 (0.01)

 − 2.36 (0.01)

0.25

 − 0.40 (0.03)

 − 0.35 (0.02)

1.22 (0.03)

1.07 (0.02)

2.89 (0.04)

2.50 (0.04)

3.90 (0.07)

VT3

0.74 (0.00)

 − 4.73 (0.07)

0.16

 − 3.10 (0.04)

 − 1.97 (0.03)

 − 0.50 (0.03)

2.10 (0.03)

VT4

0.74 (0.00)

 − 4.26 (0.06)

0.18

 − 2.55 (0.04)

 − 1.36 (0.03)

0.15 (0.03)

2.93 (0.04)

Social functioning (SF)

SF1

0.50 (0.01)

 − 1.68 (0.06)

0.07

2.80 (0.08)

5.92 (0.17)

8.66 (0.29)

SF2

0.50 (0.01)

 − 6.35 (0.18)

0.07

1.07 (0.02)

 − 3.42 (0.06)

0.28

 − 4.73 (0.13)

 − 2.58 (0.04)

 − 3.48 (0.10)

 − 1.92 (0.03)

 − 2.06 (0.07)

 − 1.15 (0.02)

 − 0.01 (0.05)

 − 0.02 (0.02)

Role emotional (RE)

RE1

1.82 (0.02)

0.35 (0.01)

0.36

RE2

1.82 (0.02)

0.23 (0.01)

0.36

1.63 (0.02)

0.24 (0.01)

0.31

RE3

1.82 (0.02)

 − 0.07 (0.01)

0.36

1.63 (0.02)

 − 0.07 (0.01)

0.32

Mental health (MH)

MH1

0.78 (0.00)

 − 4.35 (0.07)

0.19

 − 2.59 (0.04)

 − 1.53 (0.03)

 − 0.33 (0.03)

1.50 (0.03)

MH2

0.78 (0.00)

 − 4.49 (0.07)

0.18

 − 2.99 (0.04)

 − 2.12 (0.03)

 − 1.01 (0.03)

0.82 (0.03)

MH3

0.78 (0.00)

 − 11 (–)

0.19

0.79 (0.01)

 − 3.94 (0.06)

0.2

 − 2.84 (0.07)

 − 2.24 (0.03)

 − 0.42 (0.03)

 − 0.82 (0.03)

1.03 (0.03)

0.55 (0.03)

2.72 (0.04)

2.91 (0.04)

MH4

0.78 (0.00)

 − 4.83 (0.08)

0.18

0.79 (0.01)

 − 4.73 (0.07)

0.18

 − 3.18 (0.05)

 − 3.18 (0.04)

 − 2.15 (0.03)

 − 2.19 (0.03)

 − 0.82 (0.03)

 − 0.88 (0.03)

2.04 (0.03)

2.00 (0.03)

MH5

0.78 (0.00)

 − 11.18 (–)

0.18

 − 1.35 (0.04)

0.84 (0.03)

2.05 (0.03)

3.48 (0.05)

HT

0.91 (0.00)

 − 4.84 (0.09)

0.23

 − 2.59 (0.04)

 − 0.23 (0.02)

1.25 (0.03)