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By the end of this section, you will be able to:

  • Interpret a circular flow diagram
  • Explain the importance of economic theories and models
  • Describe goods and services markets and labor markets

John maynard keynes

The image is a photograph of John Maynard Keynes.
One of the most influential economists in modern times was John Maynard Keynes. (Credit: Wikimedia Commons)

John Maynard Keynes (1883–1946), one of the greatest economists of the twentieth century, pointed out that economics is not just a subject area but also a way of thinking. Keynes, shown in [link] , famously wrote in the introduction to a fellow economist’s book: “[Economics] is a method rather than a doctrine, an apparatus of the mind, a technique of thinking, which helps its possessor to draw correct conclusions.” In other words, economics teaches you how to think, not what to think.

Watch this video about John Maynard Keynes and his influence on economics.

Economists see the world through a different lens than anthropologists, biologists, classicists, or practitioners of any other discipline. They analyze issues and problems with economic theories that are based on particular assumptions about human behavior, that are different than the assumptions an anthropologist or psychologist might use. A theory    is a simplified representation of how two or more variables interact with each other. The purpose of a theory is to take a complex, real-world issue and simplify it down to its essentials. If done well, this enables the analyst to understand the issue and any problems around it. A good theory is simple enough to be understood, while complex enough to capture the key features of the object or situation being studied.

Sometimes economists use the term model    instead of theory. Strictly speaking, a theory is a more abstract representation, while a model is more applied or empirical representation. Models are used to test theories, but for this course we will use the terms interchangeably.

For example, an architect who is planning a major office building will often build a physical model that sits on a tabletop to show how the entire city block will look after the new building is constructed. Companies often build models of their new products, which are more rough and unfinished than the final product will be, but can still demonstrate how the new product will work.

A good model to start with in economics is the circular flow diagram    , which is shown in [link] . It pictures the economy as consisting of two groups—households and firms—that interact in two markets: the goods and services market    in which firms sell and households buy and the labor market    in which households sell labor to business firms or other employees.

The circular flow diagram

The circular flow diagram’s outer arrows represent a goods and services market, and the inner arrows represent a labor market. As illustrated by the outer arrows, in a goods and services market, firms give goods and services to households and, in exchange, households give payment to firms. As illustrated by the inner arrows, in a labor market, households provide labor to firms and, in exchange, firms give wages, salaries, and benefits to households.
The circular flow diagram shows how households and firms interact in the goods and services market, and in the labor market. The direction of the arrows shows that in the goods and services market, households receive goods and services and pay firms for them. In the labor market, households provide labor and receive payment from firms through wages, salaries, and benefits.

Of course, in the real world, there are many different markets for goods and services and markets for many different types of labor. The circular flow diagram simplifies this to make the picture easier to grasp. In the diagram, firms produce goods and services, which they sell to households in return for revenues. This is shown in the outer circle, and represents the two sides of the product market (for example, the market for goods and services) in which households demand and firms supply. Households sell their labor as workers to firms in return for wages, salaries and benefits. This is shown in the inner circle and represents the two sides of the labor market in which households supply and firms demand.

This version of the circular flow model is stripped down to the essentials, but it has enough features to explain how the product and labor markets work in the economy. We could easily add details to this basic model if we wanted to introduce more real-world elements, like financial markets, governments, and interactions with the rest of the globe (imports and exports).

Economists carry a set of theories in their heads like a carpenter carries around a toolkit. When they see an economic issue or problem, they go through the theories they know to see if they can find one that fits. Then they use the theory to derive insights about the issue or problem. In economics, theories are expressed as diagrams, graphs, or even as mathematical equations. (Do not worry. In this course, we will mostly use graphs.) Economists do not figure out the answer to the problem first and then draw the graph to illustrate. Rather, they use the graph of the theory to help them figure out the answer. Although at the introductory level, you can sometimes figure out the right answer without applying a model, if you keep studying economics, before too long you will run into issues and problems that you will need to graph to solve. Both micro and macroeconomics are explained in terms of theories and models. The most well-known theories are probably those of supply and demand, but you will learn a number of others.

Key concepts and summary

Economists analyze problems differently than do other disciplinary experts. The main tools economists use are economic theories or models. A theory is not an illustration of the answer to a problem. Rather, a theory is a tool for determining the answer.

Questions & Answers

what is balance of payment
Tih Reply
I don't know
balance of payment is the sum total of a country receipt for her exports and the total payments made for her imports.
discuss collusion of An oligopoly
Fikile Reply
ɧơɯ Ćąŋ ɖɛmąŋɖ Ćɧąŋɠɛ ŧơ want
henry Reply
what is money
Ngea Reply
money is everything
a regulatory object between producer and consumer of monetary system
money is anything generally accepted for the payment of goods and services and for the settlement of debt
a regulatory object of good and services between producer and consumer ( all these comes under monetary system)
what is price surveillance?
Berry Reply
what is favourable balance of trade
what is demand
Oluchi Reply
what are two classical macroeconomics and what're their theories say about their equations?
what is the formula for calculating elasticity
aza Reply
what is elasticity of demand?
Rita Reply
flexibility of demand in terms of price , income and tax ratio .
Causes of economic growth
pierre Reply
What is elasticity of demand
What are the causes of economic growth
economic growth, establishment of industry, encourage of investor's, farm productivities, creation of institutions, construction of good road etc
elasticity of demand can be said to be the responsiveness of demand to a change in prices
impact of collusion in the economy referring to inefficiencies illustrated by means of graph
nondumiso Reply
The Factor price will determine the choice of techniques to produce.Expantiate
what is elasticity of demand?
Etta Reply
state and explain two types of demand
Institution involved in money market
Gande Reply
what is Economics
Kwame Reply
Economic is the study of scarcity
Economics is the study of a lot of things. It is split up into two areas of study, Microeconomics and Macroeconomics. Microeconomics is the study of an individual's choices in the economy and Macroeconomics is the study of the economy as a whole.
Economics is a science that studies human scarcity
What is Equilibrium price?
Equilibrium is the market clearing price. The point at which quantity demanded equals quantity supplied. The point at which the supply and demand curves intersect.
Equilibrium price*
Refers to the study of how producers use limited resources to satisfy human unlimited wants
why is economics important
Derrick Reply
why economics important
name four ways to encourage the development of trade amongs country

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Source:  OpenStax, Principles of economics. OpenStax CNX. Sep 19, 2014 Download for free at http://legacy.cnx.org/content/col11613/1.11
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