The Delphi method brings subject matter experts with a range of experiences together in multiple rounds of questioning to arrive at the strongest consensus possible on a topic or series of topics (Okoli & Pawlowski, 2004; Pulat, 2014). The first round is typically used to generate the ideas for subsequent rounds’ weighting and prioritizing, by way of a questionnaire. This first round is the most qualitative of the steps. Subsequent rounds are more quantitative. According to Pulat (2014), ideas are listed and prioritized by a weighted point system with no communication between the subject matter experts. This is meant to avoid confrontation (Dalkey and Helmer, 1963). Results and available data requested by one or more experts can be shown to all experts, or new information that is considered potentially relevant by an expert (Dalkey & Helmer, 1963; Pulat, 2014).
While Delphi begins with and keeps a sense of qualitative research about it, traditional forecasting utilizes mostly quantitative methods, utilizing mathematical formulations and extrapolations as mechanical bases (Wade, 2012). Using past behavior as a predictor of future positioning, a most likely scenario is extrapolated (Wade, 2012; Wade, 2014). This scenario modeling confines planning to a formulaic process much like regression modeling. Both Delphi and traditional forecasting utilize quantitative methods, the difference being to what degree. A key question in deciding which method to use is what personalities are involved. Delphi methodology gives the most consideration to big personalities and potentially fragile egos, avoiding any direct confrontation or disagreements.
Dalkey, N., & Helmer, O. (1963). An experimental application of the Delphi method to the use of experts. Management Science, 9(3), 458-467.
Okoli, C., & Pawlowski, S. D. (2004). The Delphi method as a research tool: an example, design considerations and applications. Information & Management, 42(1), 15-29.
Pulat, B. (2014) Lean/six sigma black belt certification workshop: Body of knowledge. Creative Insights, LLC.
Wade, W. (2012) Scenario Planning: A Field Guide to the Future. John Wiley & Sons P&T. VitalSource Bookshelf Online.Most content also appears on my LinkedIn page.