Presentation (CTI)

OBJECTIVES: Delphi methods are used in healthcare decision-making and Health Economics and Outcomes Research (HEOR) to achieve expert consensus where empirical evidence is limited. Variations in design, implementation, and reporting raise questions about the methodological rigor, consistency of use, and interpretations of results. This study aims to address these methodological inconsistencies by reviewing how Delphis are applied in these fields, identifying trends, gaps, and opportunities to improve standardization and inform guidelines.
METHODS: A scoping review was conducted in Embase and Medline combining the term Delphi with HEOR-, and HTA-relevant terms. Publications discussing variability in Delphi methods and examining the methodologies used in Delphis within these domains were included. Data were charted to map methodological features of Delphi studies, providing an overview of common practices and existing guidelines.
RESULTS: The review findings indicate that the modified Delphi is the most commonly used approach in healthcare decision making and HEOR. Strengths include integrating expert judgment with existing evidence while maintaining efficiency in time and cost. This review identified two key methodological frameworks (RAND and NICE) and two main reporting standards (ACCORD and DELPHISTAR) related to the (bio)medical, social and health sciences. Nonetheless, wide variation emerged in modified Delphi’s employment, including: (1) how evidence is translated into statements - via interviews, surveys, or literature reviews - without standardized guidance on their applications; (2) the use of 2-3 predefined rounds in most studies, despite the absence of consistent application; (3) underreporting of panel selection criteria and definition of expertise, raising concerns about selection bias; (4) the establishment of consensus thresholds a priori, though their interpretation remains inconsistently guided.
CONCLUSIONS: The modified Delphi is increasingly used in healthcare and HEOR due to its efficiency and cost-effectiveness, but inconsistent methodologies and reporting highlight the need for clearer guidance to improve rigor, transparency, and reproducibility of Delphi-studies.