Delphi Study

Delphi Technique

The Delphi technique is a quantitative option aimed at generating consensus. It solicits opinions from groups in an iterative process of answering questions. After each round the responses are summarised and redistributed for discussion in the next round. Through a process of convergence involving the identification of common trends and inspection of outliers, a consensus is reached.

In its original form, question rounds are administered in writing, for instance distributed by email. The technique has been adapted for use in groups face to face with the heart of the process remaining intact, allowing individuals time to reflect and an equal opportunity to contribute, ‘using disagreement as a trigger for deeper analysis’ (Dick 2000). For instructions on how to facilitate a face to face Delphi exercise see Bob Dick’s (2000) detailed reflection .

The Delphi technique originated in the forecast of future trends and its unique contribution is the ‘boiling down’ of differing expert opinions or other stakeholders into consensus for decision making – without creating direct confrontation or allowing strong individuals to dominate the process (as often happens in face-to-face discussions).

M&E context: This technique can be used in various evaluation tasks to predict future data for instance in assessing the ‘problem’ the program aims to solve and forecasting future changes. This may support evaluation in the ‘describe’ stage, help with the setting of indicators and the development of monitoring plans or journals. Alternatively, the Delphi technique can also be applied in retrospect if monitoring and evaluation data is lacking and en evaluator seeks to gather it from stakeholders. Due to its quantitative, expert-based nature it is especially useful in judgment and forecasting of situations in which pure model-based statistical options are not practical.

Delphi, a dialectic consensus option, seeks to incorporate opposing views into a new solution in contrast to other consensus techniques, through which ‘decisions are most often taken by an arbitrator or leader or by majority vote.  To oversimplify the issue somewhat, one of the expressed views prevails’. In contrast, Delphi is useful in complex situations where there is little overlap between opposing stances and negotiation or the ‘winning’ of one side (by way of majority of power) would grossly displease another (Dick 2000).


Advice for CHOOSING this option (tips and traps)

  • This options can be used for soliciting advice from geographically dispersed, time poor experts.
  • Allows for ‘aggregation’ of quantitative data in the form of differing opinions.
  • Time intensive. The process usually includes three or four rounds, each of which must allow experts time to comment. It is therefore likely to take weeks.

Advice for USING this option (tips and traps)

  • Delphi is a useful complement to a range of other evaluation measures. Expert consensus produced by Delphi can for example inform the monitoring journals or the design of surveys for a larger audience.





Dick, B. (2000) Delphi face to face  [On line]. Resource Papers in Action Research Available at

Updated: 14th January 2014 - 1:50am


Anonymous's picture
Ruthie Bowles

I was researching for a supply chain article I'm writing, and I'm using this post as a source for the Delphi technique. Thank you very much for writing in plain English! Well written, thanks again!

Alice Macfarlan's picture
Alice Macfarlan

Thanks very much for the feedback, Ruthie! I'm glad this page was useful for you

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