The Delphi methodology is used to determine, predict and explore group attitudes, needs and priorities. This paper, the first of a two part series on the Delphi methodology, will provide nurse administrators with the basic information necessary to participate in and conduct projects using the Delphi methodology. The methodology will be defined and issues related to design, sampling, instrumentation and methods of data analysis discussed. The role of the nurse administrator, when the Delphi methodology is used, will then be addressed. In the second paper, administrative applications of the Delphi methodology will be addressed.