Vocational education research and development (R&D) product evaluations are difficult to conduct for several reasons, such as the many types of R&D products, the multiple users of the products with different goals for evaluation, the limited time available, and the high cost. In order to meet these challenges, an internal evaluation team at the National Center for Research in Vocational Education developed a conceptual framework for evaluating R&D product impact. The conceptual framework was a linear model with five stages: development, distribution, implementation, utilization, and effects. Two different types of impact criteria were presented in the framework: formative and summative. A more specific model was created to measure product impact. The formative criteria that were addressed in this model were user orientation, support systems, and integrated utilization; and the summative criteria were user satisfaction and individual growth. A modeling approach known as structural equation modeling can be used to determine the degree to which the proposed model actually represents the R&D product impact phenomenon in the population. LISREL, an acronym for linear structural relationships, is a computer program developed to analyze structural equation models. The results of a LISREL analysis will give evidence of the fit of the model in the population and the fit of individual parameters. LISREL possesses a number of features that bring enormous potential for analyzing other vocational education R&D phenomena. (References on LISREL are included in the report.) (KC)