Page "Delphi method" Paragraph 6

Different approaches were tried, but the shortcomings of traditional forecasting methods, such as theoretical approach, quantitative models or trend extrapolation, in areas where precise scientific laws have not been established yet, quickly became apparent.

To combat these shortcomings, the Delphi method was developed by Project RAND during the 1950-1960s ( 1959 ) by Olaf Helmer, Norman Dalkey, and Nicholas Rescher.

It has been used ever since, together with various modifications and reformulations, such as the Imen-Delphi procedure.