Abstract: A computer-assisted method for evaluating a product development project comprises interactively defining a plurality of development scenario models, interactively assigning a probability to each of the plurality of development scenarios to produce a plurality of corresponding probabilities, calculating a net present value for each of the development scenario models to produce a plurality of corresponding net present values, and processing the probabilities and the net present values to calculate a probability-weighted net present value for the development project. The step of defining a plurality of development scenario models includes modeling cost-generating activities and income-generating activities.