This publication assists existing and potential stakeholders in the definition of competitive approaches regarding design and deployment of small and medium sized reactors (SMR). It provides a framework for assessment of the investment attractiveness of nuclear power plant projects that adopts small reactor to be deployed in multi-modules and incorporate modularization construction technology. Main chapters detail past experience and future plans in several IAEA Member States and present the suite of models to assist designers and guide potential users on the economic performance and investment attractiveness of SMRs. A framework for the consolidated application of such models is also suggested. The annexes, contributed by Member States, provide in depth descriptions of different assessment models and give examples of their application.