VALIDATION DATA

MEASUREMENT PROPERTIES
Limitations English only
Observations
1. RELIABILITY
A. Internal Consistency Not Tested
Cronbach's (Describe)
B. Reliability intraobserver or test-retest Tested
Continuous scores: intraclass
correlation coefficient (ICC)
Dichotomus: Cohen kappa (Describe)

The BIoH questionnaire demonstrated excellent test-retest reliability (ICC 0.923, 95% CI 0.900-0.940).

C. Reliability interobserver or Measurement error Tested
Standard error of measurement (SEM),
smallest detectable change (SDC) or
Limits of agreement (LoA) (Describe)

The median difference (151.5 points) in a cohort far exceeds the smallest detectable change of 42 points previously identified.

2. VALIDITY
A. Content validity: face validity Tested
Expert opinion (relevance and
comprehensiveness) (Describe)

Patients and physiotherapists commented positively on the appropriateness, validity, acceptability and feasibility of the BIoH questionnaire. Physiotherapists assessed the interpretability of the questionnaire and commented that, whilst further information might be captured, the value of that information might be limited.

The questionnaire was considered comprehensive with only a very limited number of potential missing areas related to use of hand-held technology, hair washing/drying and intimacy. 

B. Construct Validity:
Structural validity
Tested
Hypotheses-testing Not Tested
Cross-cultural validity Not Tested
Brief Description

In a sampling frame of non-JHS responders (n = 376) and the  JHS cohort (n = 448), the median (IQR) BIoH scores  were 81 (57.25) and 231.5 (74.25) in the non-JHS and JHS samples respectively (p < 0.001). There was a very strong correlation between BIoH score and the number of painful areas (r = 0.867, p < 0.001).The observed difference, therefore, cannot be explained by measurement error and is likely to indicate a true difference.

C. Criterion validity Not Tested
Comparison with a 'gold standard' Continuous scores:
correlations, ROC curves Dichotomus:
Sensitivity & Specificity (Describe)