Duration changes and decision-making in DCE_TTO: evidence from SF-6Dv2

Area of Science:

• Health Economics
• Decision Science
• Psychometrics

Background:

• Discrete Choice Experiments (DCE) are widely used to elicit health preferences.
• Incorporating time duration as an attribute in DCE (DCE_TTO) is crucial for accurate health state valuation.
• Understanding how duration changes affect choices is vital for robust study design.

Purpose of the Study:

• To investigate the impact of modifying health state durations on participant choices within a DCE framework.
• To assess the anchoring effect and the influence of duration changes on preference shifts.
• To inform the design and interpretation of DCE_TTO studies.

Main Methods:

• A sample of the general population in Quebec, Canada, participated in a two-phase DCE_TTO study using SF-6Dv2.
• Participants completed identical choice sets in two phases: initial (DCEoriginal) and with modified durations (DCEchanged).
• McNemar's Test analyzed changes in choices before and after duration adjustments (1-20 years).

Main Results:

• A significant increase in the duration of an unchosen option (≥2x) led to it becoming the preferred choice (p<0.05).
• Decreases in the duration of a chosen option did not necessarily lead to its rejection.
• Participants exhibited a strong anchoring effect to their initial choice, with duration changes having a moderate impact on switching.

Conclusions:

• Health state duration exhibits non-linear effects on preferences in DCE_TTO.
• Anchoring effects are prominent, but duration modifications can influence choice switching.
• Findings provide critical insights for optimizing DCE_TTO design and improving the validity of health state valuations.