Comparison to Other Instruments Health Dynamics Inventory

1 comparison other instruments

1.1 reliability
1.2 validity
1.3 factor structure

comparison other instruments

the authors have used criteria specified erbes,et al., evaluate hdi. erbes, et al. considered following criteria evaluate outcomes measurement instruments: reliability; validity; factor structure; sensitivity change; scope of measurement; utility across patient populations; potential enhance critical decisions clinical care; briefness; whether instrument self-report; ease of administration; ease of interpretation; reasonable price; applicability across multiple settings; computerization capability; computer scoring , comparison standardization samples; , face validity (whether makes sense patients , clinicians). see: http://www.minneapolis.va.gov/services/ptsrt/serv_pts_our.asp

reliability

erbes et al. noted acceptable range test-retest reliability greater .70, whereas internal consistency needed greater .80. hdi meets these criteria. hdi major scales (distress, global symptoms , global impairment) , subscales have been evaluated. co-efficient alpha , gutman split half reliabilities excellent. • hdi split half reliabilities values ranged .70 substance abuse subscale .91 depression subscale •alpha .reliabilities of 72 .95 on 3 major scales , of subscales.

validity

erbes et al. required construct , criterion-related validity, is, instrument correlated other established instruments. hdi meets these criteria. major scales (distress, global symptoms , global impairment) distinguish patient , non-patient samples easily. patients score higher on of scales, expected.

in development of hdi, validity of subscales (e.g., depression, anxiety, substance abuse , psychotic thinking) evaluated comparing patients these diagnoses other patients , non-patients. results supported validity of subscales. example, patients diagnoses of depression scored higher on depression subscale both patients without such diagnosis , non-patients. same true other subscales.

in demonstration of validity, analyses indicated psychiatrist , therapist ratings of distress , impairment (as of diagnoses) correlated patient reports of distress, symptoms , impairment.

factor structure

erbes et al. considered independence of factor structures third consideration evaluating outcome measures. hdi has been extensively tested correlations between 3 major subscales, , results suggest associated independent. supports factor structure of hdi reflection of 3 major aspects of mental illness.