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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

who is the father of economics
Acquah Reply
Adam Smith...
Chris
adam smith father of modern economics alfred Marshall father of micro economics john Maynard Keynes father of macro economics
vinay
Adam smith
Esther
Adam smith is the father of classical economics.
yusuf
The economic field existed because of the limited resources and unlimited human wants. why is it so?
Eliud Reply
state the law of diminish return
Abobarin
the law of diminishing returns states that every additional increase in the variable factor of production, keeping other factors fixed, will eventually reach a point were returns will diminish with every successive unit of factor added.
Hamna
the system of economics
molos Reply
what is economics system
molos
is an arrangement for managing the relatively scarce resources in a particular place and at a particular time
Samuel
but also allocate resources equally ?
Furkan
economic is the study of what
Abba
Economics is a science which studies humam behaviour as a relationship between ends and scarce means which have alternate uses
Samuel
what is the law of equilibrium.
Henry Reply
The law of equilibrium states that when the demand of a commodity is equal to the supply
Stanley
what is demand curve
Gift
demand carve is a graphical representation of the relationship between the price of the or the service and the quantity demanded for a given period of time
Adamsvictor
Is the graphical representation of demand schedule. Also it has negative slope
Abubakary
The law of equilibrium is state that the quantity demand are equal to quantity supply.
Abubakary
sometimes demand exceeds supply or vice versa .In the first situation prices tend to rise therefore supply and demand meet the balance point called as equilibrium .
Furkan
the point of intersection mathematically but this is just an assumption that all other variables remain equal
Deleon
when there is excess supply and demand it means there is forces acting upon the equilibrium and prices should be decreased or increased appropriately
Deleon
The law of equilibrium states that ceteris paribus, at a certain two variables will be equal to each other.
Sessay
The difference between cyclical unemployment and structural unemployment
Prince Reply
Cyclical unemployment .it has to do with an increase in the quantity of good demanded or there is over production which result in fall in prices. Industries will be affected it will now causes retrenchment of workers in the industries while structural unemployment arises as a result of slight change
Adeoti
In the industrial structure of a countries workers wil now be retren
Adeoti
Will now be retrenched as a result of economic recession... That is the little i knw....
Adeoti
what is the condition of a consumer behaviour in the equilibrium under the theory of consumer behaviour
Sahr Reply
what is equilibrium
Sahr
A point where quantity demand & supply meets called equilibrium
Hasham
a state is said to be equilibrium when there is no tendency of movement.
Nibedita
Pls @Nibedita am confused
Prince
The state of balance achieved by an end user of products that refers to the amount of goods and services they can purchase given their present level of income and the current level of prices. Consumer equilibrium allows a consumer to obtain the most satisfaction possible from their income.
Okwori
where is the calculations?
Nathan Reply
what are the two conditions for aconsumer to be in the equilibrium under the theory of consumer behaviour in
Sahr
Economic equilibrium is a condition or state in which economic forces are balanced. In effect, economic variables remain unchanged from their equilibrium values in the absence of external influences. Economic equilibrium may also be defined as the point at which supply equals demand for a product,
vinay
Hello there, let's make a time to chat about econimics and its issues.
DA Reply
it's true
Adamsvictor
hie Sir /Madam l need help when it comes to Economics lm doing it for the first time
Thembelani
So, share your problems that you have in terms of economis and we will discuss on it.
DA
Basic Economic problems
Thembelani
what is the Basic Economic problem
Thembelani
what is the Basic Economic problem
Thembelani Reply
scarcity
Rhaiymornd
a bit of explanation please its my first year doing Economics
Thembelani
rare, limited. economic agents eg You dube, the govt & the business entities wants to maximise their utility/satisfaction but because limited resource or scarcity of such resources they are unable to satisfy their needs.
ian
thank u Sir , l understand what you are saying now
Thembelani
limited resources; you wanna take the most benefits from the minimum resource.
DA
if u ar a fresher, eco has to 2 fundamental parts "micro & macro". micro(small) this is were the economc agents ar discussd, economc systms, dmand & supply, typs of market systms etc and the macro (big) part the elucidates the functns of central bank, typs of employmnt, functns of money & int trade.
ian
there is an old adage that says "a picture is worth a thousand words" economics is full of graphing so it requires on the side of the student to master the art of keeping information in form graphs.
ian
oky Sir
Thembelani
scarcity becomes the fundamental problem of economics because of limited resources, when we take an individual, he or she has many wants, thus unlimited wants but can never satisfy all but only few.
Rhaiymornd
now when we take a firm, a firm maybe willing to produce two or more product into the market but due to limited resources they only produce one. the same way if we take the government, he or she maybe willing to bring development either through infrastructures,
Rhaiymornd
that is when consumer decision making rule comes in
Olusegun
choice arises as a result of scarcity of resources
Olusegun
so if we look through, the individual, firm and government, their wants are unlimited but due limited resources, all of their wants cannot be satisfy. therefore scarcity can be term as limited in supply of resources. scarcity is not lack of resources but insufficient resources
Rhaiymornd
there is a marriage with the following; scarcity, factors of production, opportunity cost curve (occ) or (ppc, ppf, tc) production possibility curve productn possibility frontier transformation curve. The OCC, PPC, PPF & TC explains the decisions made by householders, firms & the govt.
ian
opportunity cost also arises as a result of firm willing to produce a particular commodity but resources use in satisfying or producing such output is limited
Olusegun
wat ar those decisions? the most important is WHY nations economise tht is if they hav abundancy of factors of productn eg land, labour & entreprise? now since all of us have unlimited needs against few resourcs PPC, PPF, TC, OCC walks in to make wise allocatn of resources.
ian
how do those decisions made? eg by economic agents; a. Household (You) - if u have R10 & wish to buy a book & a pen & realise that both commodities seĺl at the same price which of the two (2) can u buy (necesity) and which one can u forgo (not all tht important).
ian
b. firms - they allocat mo resourcs to all thoz commoditz tht they think will yield mo profit. c. Govt - if the govt SA was to come in yo area which 1 would u think they can consider first tht can benefit the majority & the minority. So instead of building football stadium they construct a hospital.
ian
if the SA govt had enough resources they would have built both the stadium and the hospital but because of scarce in terms of resources they had to forgo the construction the stadium to build a hospital which is necessary for the majority to benefit.
ian
Opportunity cost well broken down..
Andres
opportunity cost means the lose of other alternatives when the alternative is chosen
saad Reply
is the benefits that you loose by not selecting a certain alternative.
EDWINY
individual wants maybe unlimited, but means to satisfy them are limited there one has to forgo some alternative in order to acquire other alternative and it must according priority, that is when scale of preference set in for individuals to make choice
Rhaiymornd
hello everyone
Aliyu
Next best alternative forgiven
Shoaib
demand is the amount of goods and services that consumer is willing and able to purchase at a particular prices over given period of time
Rhaiymornd Reply
yep
Abraham
what's demand?
labi Reply
What customers want the most...
Abraham
not only what customers wants, want is just mere desire but demand is backed by purchasing power, ability and willingness
Rhaiymornd
thanks
Abraham
What's opportunity cost?
Abraham
what are the differences between demand and supply
Zakariyah Reply
who is called lender of the last resort
Divyanshu Reply
Hi
Linda
hlw
Karishma
Central bank
Majeed
hy
Karishma
Hello
Majeed
hy
Karishma
How are you
Majeed
Am gud
Linda
fine
Karishma
Am gud
Linda
hello
Chandra
Well! what's going on
Majeed
r u study in economics
Karishma
anybody there?
Chandra
r u study in economics
Karishma
the central bank
Sessay
Has completed already
Majeed
hey
neha
yes
Abigail
Yesss
Majeed
ok
Karishma
hey
Doctor
yh
Abigail
more questions
Sessay
how ar you
Doctor
split the price effect into income effect and substitution effect
Karishma
fine and u
Abigail
Hi
Godwin
hi
Hey, I am new here. Hope, discussion on Economics will clear our concepts more.
yasir
yes
Abigail
do u speak hindi or english
Karishma
how to consumer equlibrium through ic
Karishma
consumer equilibrium demand equals supply
Kenneth
the consumer is in equilibrium when the indifference curve is tangential to the budget line. or when the BL and IC intersect
Sessay
reasons indifference curve slopes downwards?
Kenneth
fine Abby any good,
Doctor
ur lost
Doctor
hey. im new year. economics teacher how we can discuss some thing interesting.
EDWINY
which one
Doctor
what do u understand the concept of poverty cycle.
EDWINY
hey
Ebong
I'm New here
Ebong
hi
ian
just new here guy's and also an Economics fresher of Kogi State University Anyigba
nelson
wxup
Ayegba
who can tell the laboratory of economic?
Amara
, Dennis Weissman Associates, LLC Laboratory Economics is the monthly business newsletter that gets behind the headlines and press releases.
Ayegba
sooo teah me what an LLC
Emmanuel
what's the topic
Adamsvictor Reply
economic systems
gracious
hello
Antonio
market
aba
hello where can I find the diagrams
Manu
Hello I am totally out ,I am not understanding why we are here. can someone help me out?
Amara
why Economic is not a pure science can someone help me out
Mohamed
because economics like science put forth a some hypotheses and then do experiments to prove them
Anwesh
but these experiments are not completely controlled
Anwesh
Hello
Comfort
hey
suraj
hi people can you help me out on "demand and supply"
Milton
Am not understanding can someone enlighten me pls
Bertilla
hi people can you help me out on "demand and supply"
Sessay
hello. if Mr.Patrick's income is #900.00 while that of Mr.Shodawe is #1300.00 if Mr.Patrick and Shodowe pay #90.00 and #130.00 as taxes,the tax system is?
Benjamin
I need the answer please
Benjamin
regressive tax system
shaikh
OK thanks
Benjamin
Isn't this called proportional tax rate because the rate stays the same - 10%? Tell me if I'm wrong
Ioan

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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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