The appropriate combination of extension-teaching methods for rapid farm-technology diffusion and sustained productivity growth in the World-Bank-Assisted Agricultural Development Project in rural Nigeria is examined. The multiple extension-teaching methods in the Borin and Oyo North Projects have led to self-defeating and counterproductive results. Using principal-components analysis, the ten extension-teaching methods (variables) are transformed into a linear equation by allocating relative weights to each variable. These weights (coefficients of the equation), which are reasonably unique to each variable, measure the relative importance of the variables and therefore facilitate their ranking in each of the project districts. The usefulness of the principal component model in the World-Bank-Assisted Agricultural Development Projects in particular, and the rural Nigerian agricultural industry in general, are briefly discussed.