Skip to main content

Table 4 Tests for differential item functioning on the SF-12 mental health (MH) and physical health (PH) sub-scale items, stratified by type of joint replacement

From: Differential item functioning of the SF-12 in a population-based regional joint replacement registry

Item

THA

TKA

Δχ2

df

p-value

Δχ2

df

p-value

MH Sub-scale

 M1

20.09

6

0.003

37.03

6

< 0.001

 M2

31.85

6

< 0.001

73.22

6

< 0.001

 M3

38.30

6

< 0.001

44.61

6

< 0.001

 M4

99.26

6

< 0.001

83.93

6

< 0.001

 M5

*

*

*

*

*

*

 M6

*

*

*

*

*

*

PH Sub-scale

 P1

244.32

6

< 0.001

425.16

6

< 0.001

 P2

*

*

*

*

*

*

 P3

27.97

6

< 0.001

53.76

6

< 0.001

 P4

12.96

6

0.044

16.34

6

0.012

 P5

19.78

6

0.003

20.25

6

0.003

 P6

*

*

*

*

*

*

  1. df Degree of freedom, Δχ2 = Chi-square difference test obtained using the DIFFTEST procedure for WLSMV in MPlus; * = anchor item; All tests are statistically significant at α = 0.05
Back to article page

Health and Quality of Life Outcomes

ISSN: 1477-7525

Contact us