Risk as an attribute in discrete choice experiments: a systematic review of the literature.

BACKGROUND: Discrete choice experiments (DCEs) are used to elicit preferences of current and future patients and healthcare professionals about how they value different aspects of healthcare. Risk is an integral part of most healthcare decisions. Despite the use of risk attributes in DCEs consistently being highlighted as an area for further research, current methods of incorporating risk attributes in DCEs have not been reviewed explicitly.
OBJECTIVES: This study aimed to systematically identify published healthcare DCEs that incorporated a risk attribute, summarise and appraise methods used to present and analyse risk attributes, and recommend best practice regarding including, analysing and transparently reporting the methodology supporting risk attributes in future DCEs. DATA SOURCES: The Web of Science, MEDLINE, EMBASE, PsycINFO and Econlit databases were searched on 18 April 2013 for DCEs that included a risk attribute published since 1995, and on 23 April 2013 to identify studies assessing risk communication in the general (non-DCE) health literature. STUDY ELIGIBILITY CRITERIA: Healthcare-related DCEs with a risk attribute mentioned or suggested in the title/abstract were obtained and retained in the final review if a risk attribute meeting our definition was included. STUDY APPRAISAL AND SYNTHESIS
METHODS: Extracted data were tabulated and critically appraised to summarise the quality of reporting, and the format, presentation and interpretation of the risk attribute were summarised.
RESULTS: This review identified 117 healthcare DCEs that incorporated at least one risk attribute. Whilst there was some evidence of good practice incorporated into the presentation of risk attributes, little evidence was found that developing methods and recommendations from other disciplines about effective methods and validation of risk communication were systematically applied to DCEs. In general, the reviewed DCE studies did not thoroughly report the methodology supporting the explanation of risk in training materials, the impact of framing risk, or exploring the validity of risk communication. LIMITATIONS: The primary limitation of this review was that the methods underlying presentation, format and analysis of risk attributes could only be appraised to the extent that they were reported.
CONCLUSIONS: Improvements in reporting and transparency of risk presentation from conception to the analysis of DCEs are needed. To define best practice, further research is needed to test how the process of communicating risk affects the way in which people value risk attributes in DCEs.