Post secondary education provides an introduction to models, and develops model selection and application skills. Recent developments in cognitive psychology offer good possibilities for differentiating between levels of knowledge. It is prudent to define four levels of preparation in the technical-engineering professions, particularly in their relationship to models. As a conclusion, it turns out that professional geotechnicians are required to have MSc level of competency. The approach also yields answers to some debated questions of modelling and solving geotechnical problems in the framework of engineering mechanics.