The Wideband Delphi estimation method is a consensus-based technique for estimating effort.[1] It derives from the Delphi method which was developed in the 1950-1960s at the RAND Corporation as a forecasting tool. It has since been adapted across many industries to estimate many kinds of tasks, ranging from statistical data collection results to sales and marketing forecasts. According to the Project Management Institute, Wideband Delphi is an "estimating method in which subject matter experts go through multiple rounds of producing estimates individually, with a team discussion after each round, until a consensus is achieved."[2]