section_path: Methodology/Theoretical research
section_name: Theoretical research
paragraph_text: Theoretical research
  
  Mainstream economic theory relies upon analytical economic models. When creating theories, the objective is to find assumptions which are at least as simple in information requirements, more precise in predictions, and more fruitful in generating additional research than prior theories. While neoclassical economic theory constitutes both the dominant or orthodox theoretical as well as methodological framework, economic theory can also take the form of other schools of thought such as in heterodox economic theories.
  
  In microeconomics, principal concepts include supply and demand, marginalism, rational choice theory, opportunity cost, budget constraints, utility, and the theory of the firm. Early macroeconomic models focused on modelling the relationships between aggregate variables, but as the relationships appeared to change over time macroeconomists, including new Keynesians, reformulated their models with microfoundations, in which microeconomic concepts play a major part.
  
  Sometimes an economic hypothesis is only qualitative, not quantitative.
  
  Expositions of economic reasoning often use two-dimensional graphs to illustrate theoretical relationships. At a higher level of generality, mathematical economics is the application of mathematical methods to represent theories and analyse problems in economics. Paul Samuelson 's treatise Foundations of Economic Analysis (1947) exemplifies the method, particularly as to maximizing behavioural relations of agents reaching equilibrium. The book focused on examining the class of statements called operationally meaningful theorems in economics, which are theorems that can conceivably be refuted by empirical data.