Delphi Methods: Theory and Design Load Application

The Delphi method of highly structured group communication is described. The method is characterized by anonymity of responses from a panel of experts, controlled feedback with a statistical description of responses, and multiple iterations to reach a consensus. It is designed to extract the maximum unbiased information in reaching the most reliable results. The basic philosophy, historical development and relevance of the method to structural design loads are addressed. The Delphi method is applied to the revision of design live loads for American National Standard A58, Building Code Requirements for Minimum Design Loads in Buildings and Other Structures. A panel of 25 outstanding structural engineers was formed and two interactions used to produce final recommended changes to the standard. A detailed discussion of the conduct of the Delphi and the implementation of the changes is included. The method offers potential for additional application in structural engineering.