Harvard School basically follows the SCP paradigm, that is, the market structure-market behavior-market performance analysis framework proposed by Mei Sen and others. The market structure they studied mainly includes concentration, product differences, economies of scale, entry barriers and government regulation; Corporate behavior mainly involves collusion and strategic behavior, advertising and research and development; Market performance includes resource allocation efficiency, profit rate and productivity. Harvard School believes that there is a causal relationship between the three, market structure determines the market behavior of enterprises, and market behavior determines the performance of market resource allocation. Therefore, in order to obtain good market performance, we must adopt active anti-monopoly policies and government regulation to improve the market structure and standardize the market behavior of enterprises.

The new industrial organization theory that emerged after 1970s has the following characteristics: the research method also adopts SCP paradigm, but it no longer emphasizes market structure but highlights market behavior. Because in the short term, the market structure will not change greatly, but in the long term, the market structure, market behavior and market performance may change, and market behavior and performance will have a reaction to the market structure and cause changes in the market structure. They mainly use mathematical methods and game theory to establish a series of theoretical models to study enterprise behavior and deeply analyze economic welfare problems.