Improving the practical application of the Delphi method in group-based judgment: A six-step prescription for a well-founded and defensible process

This paper provides a practical, systematic approach to the design and delivery of a Delphi survey. We prescribe a sequence of six steps to do with (i) setting up the Delphi process – including selecting respondents and generating a requisite number of focal issues, (ii) software/delivery choice, (iii) developing question items and response scales, (iv) providing feedback between a requisite number of Delphi rounds, (v) preventing and dealing with panellist drop out, and (vi) analysing and presenting the Delphi yield. At each step, the Delphi administrator has a range of choice options and we provide discussion of the pros and cons of each option - in order that the overall design and delivery of a particular Delphi survey is both well-founded and defensible. •This paper provides detailed guidance for anyone looking to run a Delphi exercise.•The Delphi process can be broken into 6 key steps.•The paper identifies and recommends decisions to be taken at each step.•The paper also reviews and evaluates recommendations for a defensible Delphi"•Following the “6 steps of Delphi” will help generate effective Delphi output.