Stated preferences in the Iranian health system: a systematic review of discrete choice experiments and conjoint analysis

BACKGROUND: Discrete choice experiments (DCEs) are increasingly used in health to determine preferences and inform policy decisions. However, questions remain about adherence to best practices and validity of the studies. To date, no systematic review has synthesised the application of DCEs in health in Iran. We conducted a systematic review to examine characteristics, methods, quality, and topics of DCEs in Iran. METHODS: We conducted a systematic search of PubMed, CINAHL, PsycINFO, Web of Science, and Scopus. Studies were included if they collected participants' preferences for a health-related topic among relevant stakeholders using DCEs, conjoint analyses, or best-worst scaling. Data was extracted on study design, participants, attribute and choice set development, data collection, and estimation approaches. The quality of each study was assessed against good practice criteria. RESULTS: Thirty studies met the eligibility criteria. The number of DCEs published increased from 2021 onwards. Most studies were conducted in urban areas, particularly in Tehran, the capital city, and focused on health services and workforce. Attributes were generally related to monetary, time, risk, or health outcomes. Pilot testing and qualitative work with target population to inform attribute selection and questionnaire design were conducted inconsistently. Nearly half of the studies used effective designs. However, reporting on key methodological elements such as software used, blocking, and opt-out options was often incomplete. Estimation approaches varied, with conditional logit models being most commonly used. CONCLUSIONS: This is the first systematic review of DCEs on health-related topics in Iran. Although the use of this method is expanding rapidly, gaps remain in questionnaire design, method reporting, and econometric modelling. Future DCEs would benefit from including more diverse populations, improving methodological rigour, and aligning objectives with target populations. Strengthening these aspects will improve the validity and policy relevance of DCEs in Iran.