An outline of the Delphi technique of long-range forecasting by separately eliciting and refining the opinions of a group of advisers without contact among them, and calculating a statistical "group response." The procedure was designed to overcome the disadvantages common to committees and small groups. The experts reply to written questionnaires or an online computer, receive statistical feedback through formal lines of communication, and resubmit their estimates. Where the response is a number (such as a date or amount), the most useful index has been the median of the individual estimates. During the process, opinions do converge; where answers can be checked against reality, it is found that the median response tends to move in the direction of the true answer. Self-confidence is not correlated with individual performance, but the subgroup with the highest self-ratings for competence will consistently perform slightly better than the group as a whole.
This report is part of the RAND Corporation Paper series. The paper was a product of the RAND Corporation from 1948 to 2003 that captured speeches, memorials, and derivative research, usually prepared on authors' own time and meant to be the scholarly or scientific contribution of individual authors to their professional fields. Papers were less formal than reports and did not require rigorous peer review.
Permission is given to duplicate this electronic document for personal use only, as long as it is unaltered and complete. Copies may not be duplicated for commercial purposes. Unauthorized posting of RAND PDFs to a non-RAND Web site is prohibited. RAND PDFs are protected under copyright law. For information on reprint and linking permissions, please visit the RAND Permissions page.
The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.