Are Healthcare Choices Predictable? The Impact of Discrete Choice Experiment Designs and Models.

BACKGROUND: Lack of evidence about the external validity of discrete choice experiments (DCEs) is one of the barriers that inhibit greater use of DCEs in healthcare decision making. OBJECTIVES: To determine whether the number of alternatives in a DCE choice task should reflect the actual decision context, and how complex the choice model needs to be to be able to predict real-world healthcare choices. METHODS: Six DCEs were used, which varied in (1) medical condition (involving choices for influenza vaccination or colorectal cancer screening) and (2) the number of alternatives per choice task. For each medical condition, 1200 respondents were randomized to one of the DCE formats. The data were analyzed in a systematic way using random-utility-maximization choice processes. RESULTS: Irrespective of the number of alternatives per choice task, the choice for influenza vaccination and colorectal cancer screening was correctly predicted by DCE at an aggregate level, if scale and preference heterogeneity were taken into account. At an individual level, 3 alternatives per choice task and the use of a heteroskedastic error component model plus observed preference heterogeneity seemed to be most promising (correctly predicting >93% of choices). CONCLUSIONS: Our study shows that DCEs are able to predict choices-mimicking real-world decisions-if at least scale and preference heterogeneity are taken into account. Patient characteristics (eg, numeracy, decision-making style, and general attitude for and experience with the health intervention) seem to play a crucial role. Further research is needed to determine whether this result remains in other contexts.

Effects of dissuasive packaging on young adult smokers.

BACKGROUND: Tobacco industry documents illustrate how packaging promotes smoking experimentation and reinforces existing smokers' behaviour. Plain packaging reduces the perceived attractiveness of smoking and creates an opportunity to introduce larger pictorial warnings that could promote cessation-linked behaviours. However, little is known about the effects such a combined policy measure would have on smokers' behaviour. METHODS: A 3 (warning size) *4 (branding level) plus control (completely plain pack) best-worst experiment was conducted via face-to-face interviews with 292 young adult smokers from a New Zealand provincial city. The Juster Scale was also used to estimate cessation-linked behaviours among participants. RESULTS: Of the 13 options tested, respondents were significantly less likely to choose those featuring fewer branding elements or larger health warnings. Options that featured more branding elements were still preferred even when they also featured a 50% health warning, but were significantly less likely to be chosen when they featured a 75% warning. Comparison of a control pack representing the status quo (branded with 30% front of pack warning) and a plain pack (with a 75% warning) revealed the latter would be significantly more likely to elicit cessation-related behaviours. CONCLUSIONS: Plain packs that feature large graphic health warnings are significantly more likely to promote cessation among young adult smokers than fully or partially branded packs. The findings support the introduction of plain packaging and suggest use of unbranded package space to feature larger health warnings would further promote cessation.