Skip to main content

Table 2 Description of SCQ scores, reliability, item convergent and discriminant validity, and meaningfulness

From: Assessing the impact on caregivers of patients with schizophrenia: psychometric validation of the Schizophrenia Caregiver Questionnaire (SCQ)

   

Reliability

Confirmation of the structure

Meaningfulness

        

Distribution-based methods

Anchor-based methods

         

Patient minimally improved

Patient minimally worsened

SCQ domains

# of item

Mean Score (SD)

Cronbach’s alfa*

ICC*

Item-domain correlationsa

# items meeting convergent validityb

# items meeting discriminant validityc

SD \( \times \sqrt{\left(1-\alpha \right)} \)

Mean change

Mean change

HI-TS

17

27.8 (23.4)

0.96

0.87

-

-

-

5.13

-3.96

7.67

HI-P

3

27.0 (27.3)

0.85

0.82

0.62-0.75

100 %

33 %

11.09

-6.75

10.42

HI-E

6

30.0 (24.8)

0.89

0.81

0.63-0.75

100 %

83 %

8.59

-2.23

8.78

HI-S

3

26.4 (26.1)

0.80

0.75

0.60-0.66

100 %

0 %

12.21

-3.16

1.49

HI-DL

5

26.5 (24.3)

0.87

0.81

0.59-0.76

100 %

40 %

9.26

-4.83

8.39

EC

2

19.9 (24.7)

0.69

0.76

0.49

100 %

100 %

14.37

-0.86

3.13

FA

1

32.0 (36.0)

NA

0.63

NA

NA

NA

NA

-6.90

8.04

PD

2

36.7 (27.5)

0.57

0.75

0.37

0 %

0 %

18.64

-8.62

6.25

WP

2

42.0 (28.7)

0.70

0.75

0.54-0.71

100 %

100 %

12.93

-7.04

6.55

PC

3

34.0 (29.9)

0.79

0.71

0.71

100 %

100 %

12.45

-1.29

4.02

FDP

1

37.9 (39.6)

NA

0.70

NA

NA

NA

NA

-8.62

-2.68

FIC

1

26.0 (32.1)

NA

0.75

NA

NA

NA

NA

0.86

1.79

ODC

1

28.6 (31.6)

NA

0.75

NA

NA

NA

NA

-6.90

16.96

  1. SD Standard deviation; α = reliability coefficient (Cronbach’s α); ICC Intraclass correlation coefficient, NA not applicable as single-item dimension, HI-TS Humanistic impact – total score, HI-P Humanistic impact - Physical, HI-E Humanistic impact - Emotional, HI-S Humanistic impact - Social, HI-DL Humanistic impact - Daily life, EC Exhaustion with caregiving, FA Feeling alone, PD Patient Dependence, WP Worries for the patient, PC Perception of caregiving, FDP Financial dependence of the patient, FIC Financial impact of caregiving, ODC Overall difficulty of caregiving
  2. Description of SCQ scores, internal consistency reliability and item convergent and discriminant validity data were obtained at baseline in the caregiver analysis set (N = 358). Test-retest reliability data were obtained between baseline and month 3 in caregivers whose patient’s severity was stable between the two assessments (N = 147). Analyses supporting meaningful change in SCQ domain scores were calculated using distribution-based methods at baseline in the caregiver analysis set (N = 358) and anchor-based methods in patients minimally improved at Month 6 (N = 58) and patients minimally worsened (N = 28)
  3. *Reliability coefficient is considered acceptable if > 0.70
  4. aRange of correlations between each item and its domain score
  5. bItem convergent validity criterion: correlation between an item and its domain score should be ≥0.40
  6. cItem discriminant validity criterion: each item should correlate higher with its domain score than with the other domain scores
Back to article page

BMC Psychiatry

ISSN: 1471-244X

Contact us