Microeconomics

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Microeconomics is the branch of economics that deals with transactions between suppliers and consumers, acting individually or in groups. It is conventionally defined as being concerned with the allocation of scarce resources among alternative uses, but it is really about such down-to-earth matters as the way consumers' and suppliers' decisions affect the prices and the output of goods and services. Its practical importance arises from the influence of those decisions upon people's wellbeing. Although it may seem to be about money-related matters, its scope is in fact much wider. It is about how all sorts of needs and preferences can be met by mutually advantageous transactions.

Microeconomics employs many terms that are part of everyday conversation, such as "supply and demand" and "welfare", but it often defines them more narrowly. If confusion is to be avoided, some attention has to be given to its terminology and its basic concepts before attempting to understand its prescriptions and policy implications.

The nature of economic activity

Economic activity consists essentially of exchanges that take advantage of the existence of inter-personal differences. If two people have different skills, for example, both can benefit from an arrangement under which each concentrates on what he does best and exchanges what he produces with the other - an arrangement known as the division of labour. At first sight it might seem that each would have to be better than the other at some at some useful activity. In fact that is not necessary. The law of comparative advantage proves that, even if one them had an absolute advantage in every type of activity, both would benefit if each person concentrated upon what he does best and exchanged the product with the other person. For example, a writer of best-sellers who was better at plumbing than any of the available plumbers should nevertheless stick to his writing and hire a plumber. What is true of skill differences is true also of other advantages, such as the possession of different tools or access to more fertile land. (And what is true of persons is true also of countries, making comparative advantage the driving force of international trade.)

In examining production and consumption as though they are separate activities it is important to remember that in reality they are interdependent, and that neither can survive without the other. (The fact that they are usually connected by monetary transactions is, strictly speaking, irrelevant. In microeconomic activity money serves only as convenient measuring-stick - unlike the more important part it plays in macroeconomics.) Microeconomics, like macroeconomics is the study of an interactive system which can yield misleading conclusions if any individual component is considered in isolation

Production

The factors of production are normally taken to include:

• land - taken to mean all natural resources - and otherwise distinguished from the other factors by the fact that its supply cannot be increased;
• labour - taken to cover both the number of people engaged in production and the aggregate of their productive abilities;
• capital - taken to mean assets which have been produced for use in production.

(some economists also take entrepreneurship to be a factor)

Economists have created a number of generalisations about the relations between the uses of the factors of production and the output that results.

• 'diminishing returns' refers to the observation that if one only of the factors is progressively increased, leaving the others unchanged, output rises, at first in proportion, but subsequently less than proportionately to the rising input. For example, although doubling the number of workers on a building site might get the job done twice as fast, it does not follow that trebling that number would get it done three times as fast.
• 'returns to scale' refers to the observation that a simultaneous increase in all of the factors of production will often lead to a more than proportionate increase in output. If a retailer increases the number of his outlets he can often make more economical use of his warehousing and distribution facilities.
• the 'production possibility frontier' is the limiting set of output combinations of a multi-product firm. Textbooks usually deal with the simplest two-product case, which they illustrate with a diagram. For a car manufacturer that also produces tractors, the diagram depicts a situation in which car output has to fall faster and faster if tractor output is to be increased. The diagram illustrates the useful concept of an opportunity cost. For the car manufacturer working at a given output combination, the opportunity cost of making one more tractor is the reduction in car output that would be needed.

Logic requires that the output of a profit-maximising firm has to be at such a level that the production of one additional unit would bring in as much revenue as it would cost to produce. Economists usually state that condition as marginal revenue must equal marginal cost. That is one of the theorems of the theory of the firm and the concept of marginal cost plays an important part elsewhere in the study of microeconomics.

The consumer

Economists refer to the desirability of a product to a consumer as its utility. There is, of course, no way of measuring the amount of utility that a consumer derives from a product, but it is possible to say whether he gets more utility from one product than from another. That is the basis of the economic concept of indifference. The indifference curve depicts a set of combinations of two products that is so constructed that the consumer is indifferent among them. It can be thought of as the consumer’s counterpart of the production possibilities curve, above, and it is similarly a two-dimensional simplification of what is really a multi-dimensional situation. The slope of the indifference curve at a given point represents what is termed the consumer's marginal rate of substition between the two products at that point. If, when in possession of a particular combination of apples and pears, a consumer is willing to give up an apple in exchange for two pears, then that is his marginal rate of substition of apples for pears. (The marginal rate of substitution is sometimes referred to as the ratio of the marginal utilities of the two products.)

The amount of a product that the consumers are prepared to buy is influenced also by the price that they would have to pay for it and by what they can afford. Consumers’ response to changes of price is referred to as their price elasticity of demand, which is the percentage increase in the amount they would be prepared to buy in response to a one percent reduction in price. Their response to changes in their income is referred to as their income elasticity of demand, which is the percentage increase in the amount they would be prepared to buy in response to a one percent increase in their income

Markets

(to includecompetition)

How it works out

(to includeeconomic efficiency)

Welfare consequences

(to include economic welfare)