Educational Materials for Health-Related Discrete Choice Experiments: A Theory-Driven Approach

BACKGROUND: To make informed choices in health-related discrete choice experiments (DCEs), respondents need to understand the choice scenarios, alternatives, attributes and attribute levels presented to them. Respondent populations are often highly diverse in knowledge and experience, leading to varying informational needs that make it challenging to design educational materials that sufficiently inform all respondents without disengaging others. At present, however, structured guidance on developing DCE educational materials is lacking. Drawing on the instructional design literature, this paper investigates whether theory-driven adaptations to educational materials improve respondent comprehension and engagement in health-related DCEs. METHODS: Informed by three focus groups on DCE informational needs, we identified four design principles from the instructional design literature relevant to DCE educational materials: whole-task instruction, making inferences explicit, adapting information to respondents' prior knowledge and embedding self-check questions with corrective feedback. Educational materials for three existing DCEs (influenza vaccination, colorectal cancer screening and rheumatoid arthritis prevention) were redesigned to incorporate these principles. Panel respondents (N = 1754) were randomized to receive either the original or the adapted educational materials, and effects on comprehension, engagement, internal validity and choice consistency were assessed. RESULTS: Adapted materials increased time spent on educational content and were associated with small improvements in selected comprehension outcomes, though effects were often not statistically significant against the co-created comparator. Self-check questions revealed considerable comprehension gaps regardless of condition, underscoring that co-creation and pre-testing alone do not guarantee sufficient respondent comprehension. Educational materials also emerged as a meaningful source of selective dropout in all surveys, predominantly among respondents with lower education levels, posing a risk to sample representativeness that warrants attention in future research. DISCUSSION: Adapting DCE educational materials based on educational theory and instructional design principles offers a promising approach to improving respondent engagement and understanding. To enable cumulative learning, we further encourage researchers to report comprehension outcomes and publish educational materials as supplementary materials.