Scoring the Icecap-a capability instrument. Estimation of a UK general population tariff

Area of Science:

• Health Economics
• Psychometrics
• Social Sciences

Background:

• The Investigating Choice Experiments Capability Measure for Adults (ICECAP-A) is a novel measure for assessing adult capabilities.
• Economic evaluation in health and public policy requires robust capability measures.

Purpose of the Study:

• To determine the relative importance (weights) of the five attributes within the ICECAP-A measure using best-worst scaling (BWS).
• To develop a population tariff for the ICECAP-A measure to facilitate its use in economic evaluations.

Main Methods:

• A best-worst scaling (BWS) study was conducted with 413 UK adults.
• A main effects plan plus foldover design was employed for attribute level weighting.
• Scale-adjusted latent class analysis was used to account for preference and scale heterogeneity.

Main Results:

• A population tariff was estimated, assigning weights to ICECAP-A attributes.
• 'Attachment' and 'stability' accounted for approximately 22% each of the total value.
• 'Autonomy', 'achievement', and 'enjoyment' accounted for approximately 18% each.
• Greater value was placed on improvements at lower capability levels compared to higher levels.

Conclusions:

• The developed population tariff provides a framework for utilizing ICECAP-A in economic evaluations.
• The findings support the application of ICECAP-A across health and broader public policy domains.
• The study demonstrates the utility of BWS for valuing multi-attribute capability measures.