The article considers the specifics of economic models and the problems associated with the definition of its key characteristics. The author offers the solution for the issue of the model quality based on the assessment of the system of its ideas. On the basis of the review of traditional approaches to the model, the paper demonstrates the model’s multifaceted status in economic theory. Moreover, the author introduces the alternative characteristic of a model called the system of ideas of a model. The author shows that the model’s ideas system is one of the most significant components of the model, as it reflects the views and approach of the author to the solution of certain economic problems within the context of certain conditions and designated historical framework. I substantiate the key importance of the model’s ideas system for understanding the model’s value. Based on the analysis of the works of R. Solow and T. Swan, the author formulated the system of ideas of the R. Solow model, in which, their ideas of the interrelation between economy and the nature of economic processes were implemented. The main research methods are theoretical methods, including analysis and synthesis. The author also applied the methods of historical research of the foundations of economic models. The article focuses on the reflection and development of the ideas of Solow model in the works of modern authors. The article highlights the question about the correspondence between the ideas system in the works of R. Solow and T. Swan and its reflection in the papers of modern authors who use the model for the further research. The results of this study indicate that it is important to analyze the system of ideas, which underlie any economic model. Moreover, the assessment of the application of the ideas systems of fundamental economic models influences significantly the accuracy of new models developed on their basis.