The Delphi technique is a useful method for surveying informed opinion but researchers should be aware of all its pros and cons, suggests Ruth Beretta

The Delphi technique takes its name from the Greek god Apollo Pythias who, as master of Delphi, was renowned for his ability to predict the future. It has been defined by Reid (1) as: ‘A method for the systematic collection and aggregation of informed judgements from a group of experts on specific questions or issues.’ It is essentially a series of questionnaires; the first questionnaire sets out to gain a response to a broad subject and the subsequent questionnaires are built upon the responses of the preceding questionnaire (2). Three to five questionnaires may be required before consensus is reached.