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Table 6 Scale reliability and homogeneity

From: Health-Related Quality of Life in people with Multiple Sclerosis: How does this Population Compare to Population-based Norms in Different Health Domains?

Data quality indicators   Satisfactory Norms
1. Completeness of Data…………………
Items with 5% or more missing values:
NONE
99.6% YES 90
2. Responses within Range……………….
Items with 5% or more out-of-range values:
NONE
100.0% YES 100
3. Consistent Responses………………… 92.5% YES 90
4. Estimable Scale Scores………………….    
Estimable without MDE 96.7% YES 90
Estimable with Half-Scale MDE 100.0%   
Estimable with Full MDE 100.0%   
5. Item Internal Consistency
Items that failed internal consistency test:
NONE
100.0% YES 90
6. Discriminant Validity
Items that failed discriminant validity test:
MH03
99.6% YES 80
7. Reliable Scales
Scales that failed reliability criteria:
NONE
   
Scale K Rtt Rii
PF—Physical Functioning 10 0.948 0.644
RP—Role Physical 4 0.945 0.810
BP—Bodily Pain 2 0.914 0.841
GH—General Health 5 0.827 0.489
VT—Vitality 4 0.883 0.654
SF—Social Functioning 2 0.784 0.645
RE—Role Emotional 3 0.900 0.749
MH—Mental Health 5 0.875 0.583
  1. k = Number of Items
  2. Rtt = Cronbach's Alpha
  3. Rii = Average inter-item correlation