OBJECTIVES: A growing number of studies across disciplines have sought to investigate the impact of presentation differences in a discrete choice experiment (DCE) on the resulting findings. As far as the authors are aware, there has been no review dedicated to investigating the DCE literature, as a whole, in relation to the influence of differences in DCE presentation on results. Hence, the aim of this study was to conduct a scoping review to identify and summarise existing literature that compares DCE presentation differences using between-subject designs.

METHODS: The scoping review identified records between January 2011 to November 2018. A combination of terms to identify DCEs investigating presentation differences was used as searches. Searches were conducted in EBSCO Host, Pubmed, Scopus (Elsevier) and Web of Science Core Collection. 3714 unique records were identified and were screened based on title, abstract and full text. 69 articles were included in the review.

RESULTS: Three broad overarching types of presentation differences were identified in included studies. This included differences in how information or the content of the DCE is presented to respondents e.g. text phrased differently or use of alternative formats to text. Researchers also varied the amount of information provided depending on arm assignment. There were also studies, where researchers systematically varied where the number of options, attributes or levels between arms. In the vast majority of studies, some difference by arm was reported.

CONCLUSIONS: There are many studies in the DCE literature that have sought to compare presentation differences in DCEs and their impact on findings. The current scoping review and previous findings suggests a bias towards publishing studies that find significant differences between arms. However, situations where presentation differences do not affect results are important for health DCE researchers. Publication of papers that find no significant differences between arms are encouraged.