Successfully building a model requires a combination of expertise in the problem domain and in the practice of modeling and simulation (M&S). Model verification, validation, and testing (VV&T) are essential to the consistent production of models that are useful and correct. There are significant communities of domain experts that build and use models without employing dedicated modeling specialists. Current modeling tools relatively underserve these communities, particularly in the area of model testing and evaluation. This paper describes several techniques that modeling tools can use to support the domain expert in performing VV&T, and discusses the advantages and disadvantages of this approach to modeling