BACKGROUND: The Health Anxiety Inventory (HAI), the Illness Attitude Scales (IAS), and the Whiteley Index (WI) are three of the most widely used health anxiety measures, but their psychometric properties have not been investigated when administered via the Internet.
METHODS: We investigated the three instruments' test-retest reliability, internal consistency, convergent, and discriminant validity and sensitivity to change using one sample (n=111) of participants with severe health anxiety and one sample of healthy controls (n=92).
RESULTS: The HAI, IAS, and WI showed high test-retest reliability (rs≥.80), good convergent, and discriminant validity and were sensitive to detect change. The HAI and IAS (αs≥.85), but not the WI (αs≤.60) demonstrated high internal consistency.
CONCLUSIONS: The HAI, IAS, and WI have good psychometric properties, except for the low internal consistency of WI, when used as Internet-administered measures of health anxiety. Using these measures over the Internet offers highly important advantages such as increased ease of administration, reduced attrition, and cost-efficient treatment evaluation.
2015. Vol. 31, 32-37 p.