Exploration of the content validity and feasibility of the EQ - 5 D - 3 L , ICECAP - O and ASCOT in older adults Chapter 7

BACKGROUND In economic evaluations of care services for older adults health-related quality of life (QoL) measures such as the EQ-5D are increasingly replaced by the ICECAP-O and ASCOT, which cover a broader scope of QoL than health alone. Little is known about the content validity and feasibility of these measures. The purpose of this study was to explore the content validity and feasibility of the EQ-5D-3L, ICECAP-O and ASCOT in older adults. METHODS Ten older adults were purposively sampled using a maximum variation principle. Think-aloud and verbal probing techniques were used to identify response issues encountered during the interpretation of items and the selection of response options. We used constant comparative methods to analyse the data. RESULTS Two types of response issues were identified for various items in all three measures: interpretation issues and positive responses. Issues with the mapping of a response on one of the response options were least often encountered for the EQ-5D-3L items. Older adults considered the items of the ICECAP-O and ASCOT valuable though more abstract than the EQ-5D-3L. CONLUSIONS Researchers who intend to use the EQ-5D, ICECAP-O or ASCOT in economic evaluations of care services for older adults, should be aware of the response issues that occur during the administration of these measures. Older adults perceived none of the measures as providing a comprehensive picture of their QoL. A preference from older adults for one of the measures depends on the extent to which the items reflect current personal concerns in life.