Simulation models are tools used to evaluate the risk of insect pests evolving resistance to transgenic crops. Approval of new transgenic products and regulation of grower production practices are partially based on model results. Researchers developing these models differ in their interpretation of the factors most relevant to selection and in the mathematical approaches they use for evaluating evolutionary risk. Modelers need to address such questions as: Are stochastic methods necessary or is a deterministic approach sufficient? Is spatial or temporal variability more important or should both be given equal weight? How do we compare the influence of grower adoption rates to the influence of the insect’s dispersal behavior in different ecosystems? A cooperative EPA-USDA project was established to compare models and evaluate how different techniques affect the results. We report results of these efforts and identify standards and methods that have emerged.