Causes of bias in Delphi studies and consensus statements: a methodological review.

The Delphi methodology is a widely-used tool for achieving expert consensus in healthcare, particularly in areas where empirical evidence is limited or uncertain. Despite its structured design, the Delphi process remains vulnerable to implicit cognitive biases that may influence judgement and group decision-making. Such biases may inadvertently affect the quality of the consensus process, allow louder voices to influence outcomes, restrict inclusivity and undermine the validity, transparency and evidence-based nature of recommendations. We conducted a methodological review synthesising literat