This report describes an analytic training Device Effectiveness Forecasting Technique known as DEFT. DEFT accounts for device effectivness in terms of several different criteria and classes of independent predictor variables. In its present form, DEFT is a series of interactive, menu-driven computer programs that provide for three levels of device evaluation. The level of analysis is chosen as a function of the type of input data that are available and the degree of diagnosticity that is needed. The report includes a DEFT User's Manual and listings of DEFT programs. (Author)