Winter 1991 // Volume 29 // Number 4 // Tools of the Trade // 4TOT5
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The Delphi-An Evaluation Tool
Abstract
The Delphi technique consists of three or four rounds of questionnaires mailed to a panel of experts. Strengths of the Delphi are its combination of qualitative (written) and quantitative (numerical) data and its ability to form a consensus of expert opinion. Limitations are time involved for mailing and receiving replies and lack of stimulation from face-to-face contact.
Selection of an appropriate information collection strategy is important to evaluation. A solid base of evidence is essential for reputable evaluations. The choice is based on considerations such as cost, reliability, validity, relevance, and political advisibility.1 An Extension educator must be familiar with various strategies to select and use the most appropriate evaluation method.
The Delphi is an information collection strategy particularly suited for evaluations that focus on: "What do we need?" Named after an oracle that predicted the future, it has been used extensively in forecasting technological developments.2
The Delphi technique consists of three or four rounds of questionnaires mailed to a panel of experts. The first round consists of a few open-ended questions. Group responses are then mailed to the experts so they may independently and anonymously respond to the panel summary. Experts receive a reminder of their own responses and are asked to justify their deviation from the panel's majority judgment. Anonymous responses ensure a nonthreatening format that prevents one expert's opinion from dominating the views of others.
Many variations of the Delphi exist, but essential components are sequential questionnaires, continual feedback, and anonymous experts.3 The Delphi is ideally suited for needs assessments or analyses of future directions when experts are widely scattered or likely to have diverse opinions. Typical questions are: "What are the problems?" "What are possible solutions?"
The data are analyzed and presented simply. A summary of the analysis of the previous questionnaire is usually included with the next round of the questionnaire.
Strengths of the Delphi are its combination of qualitative (written) and quantitative (numerical) data and its ability to form a consensus of expert opinion. Limitations are time involved for mailing and receiving replies and lack of stimulation from face-to-face contact.
Footnotes
1. Blaine Worthen and James Sanders, Educational Evaluation: Alternative Approaches and Practical Guidelines (New York: Longman, 1984).
2. J. G. Gross, "Delphi: A Program Planning Technique," Journal of Extension, XIX (May/June 1981), 23-28.
3. C. M. Moore, Group Techniques for Idea Building (Beverly Hills: Sage Publications, 1987).