The workgroup developed a multi-step process for guideline development known as the Delphi-Nominal Group-Delphi-Field Testing (DNDF) methodology, which includes a review of scientific and gray (unpublished) literature, a Delphi survey of practice, a nominal group meeting to clarify discrepancies, a formulation of recommendations and a second Delphi round to assess the degree of consensus with the proposed recommendations. External review and field testing are also built into the process.

For more information about the DNDF Model and Methodology, see Bridging evidence and consensus methodology for inherited metabolic disorders: creating nutrition guidelines.