Fundamental Principles of Managerial Economics- Incremental Principle, Marginal Principle, Opportunity Cost Principle, Discounting Principle, Concept of Time Perspective Principle, Equi-Marginal Principle
Managerial Economics is both conceptual and metrical. Before the substantive decision problems which fall within the purview of managerial economics are discussed, it is useful to identify and understand some of the basic concepts underlying the subject.
Economic theory provides a number of concepts and analytical tools which can be of considerable and immense help to a manager in taking many decisions and business planning. This is not to say that economics has all the solutions. In fact, actual problem solving in business has found that there exists a wide disparity between economic theory of the firm and actual observed practice.
Therefore, it would be useful to examine the basic tools of managerial economics and the nature and extent of gap between the economic theory of the firm and the managerial theory of the firm. The contribution of economics to managerial economics lies in certain principles which are basic to managerial economics. There are six basic principles of managerial economics. They are:-
- The Incremental Principle
The incremental concept is probably the most important concept in economics and is certainly the most frequently used in Managerial Economics. Incremental concept is closely related to the marginal cost and marginal revenues of economic theory.
The two major concepts in this analysis are incremental cost and incremental revenue. Incremental cost denotes change in total cost, whereas incremental revenue means change in total revenue resulting from a decision of the firm.
The incremental principle may be stated as follows:
A decision is clearly a profitable one if
(i) It increases revenue more than costs.
(ii) It decreases some cost to a greater extent than it increases others.
(iii) It increases some revenues more than it decreases others.
(iv) It reduces costs more than revenues.
- Marginal Principle
Marginal analysis implies judging the impact of a unit change in one variable on the other. Marginal generally refers to small changes. Marginal revenue is change in total revenue per unit change in output sold. Marginal cost refers to change in total costs per unit change in output produced (While incremental cost refers to change in total costs due to change in total output). The decision of a firm to change the price would depend upon the resulting impact/change in marginal revenue and marginal cost. If the marginal revenue is greater than the marginal cost, then the firm should bring about the change in price.
- The Opportunity Cost Principle
Both micro and macro economics make abundant use of the fundamental concept of opportunity cost. In everyday life, we apply the notion of opportunity cost even if we are unable to articulate its significance. In Managerial Economics, the opportunity cost concept is useful in decision involving a choice between different alternative courses of action.
Resources are scarce, we cannot produce all the commodities. For the production of one commodity, we have to forego the production of another commodity. We cannot have everything we want. We are, therefore, forced to make a choice.
Opportunity cost of a decision is the sacrifice of alternatives required by that decision. Sacrifice of alternatives is involved when carrying out a decision requires using a resource that is limited in supply with the firm. Opportunity cost, therefore, represents the benefits or revenue forgone by pursuing one course of action rather than another.
The concept of opportunity cost implies three things:
(i) The calculation of opportunity cost involves the measurement of sacrifices.
(ii) Sacrifices may be monetary or real.
(iii) The opportunity cost is termed as the cost of sacrificed alternatives.
Opportunity cost is just a notional idea which does not appear in the books of account of the company. If resource has no alternative use, then its opportunity cost is nil.
In managerial decision making, the concept of opportunity cost occupies an important place. The economic significance of opportunity cost is as follows:
(i) It helps in determining relative prices of different goods.
(ii) It helps in determining normal remuneration to a factor of production.
(iii) It helps in proper allocation of factor resources.
- Discounting Principle
This concept is an extension of the concept of time perspective. Since future is unknown and incalculable, there is lot of risk and uncertainty in future. Everyone knows that a rupee today is worth more than a rupee will be two years from now. This appears similar to the saying that “a bird in hand is more worth than two in the bush.” This judgment is made not on account of the uncertainty surrounding the future or the risk of inflation.
It is simply that in the intervening period a sum of money can earn a return which is ruled out if the same sum is available only at the end of the period. In technical parlance, it is said that the present value of one rupee available at the end of two years is the present value of one rupee available today. The mathematical technique for adjusting for the time value of money and computing present value is called ‘discounting’.
- Concept of Time Perspective Principle
The time perspective concept states that the decision maker must give due consideration both to the short run and long run effects of his decisions. He must give due emphasis to the various time periods. It was Marshall who introduced time element in economic theory.
The economic concepts of the long run and the short run have become part of everyday language. Managerial economists are also concerned with the short run and long run effects of decisions on revenues as well as costs. The main problem in decision making is to establish the right balance between long run and short run.
In the short period, the firm can change its output without changing its size. In the long period, the firm can change its output by changing its size. In the short period, the output of the industry is fixed because the firms cannot change their size of operation and they can vary only variable factors. In the long period, the output of the industry is likely to be more because the firms have enough time to increase their sizes and also use both variable and fixed factors.
In the short period, the average cost of a firm may be either more or less than its average revenue. In the long period, the average cost of the firm will be equal to its average revenue. A decision may be made on the basis of short run considerations, but may as time elapses have long run repercussions which make it more or less profitable than it at first appeared.
- Equi-Marginal Principle
One of the widest known principles of economics is the equi-marginal principle. The principle states that an input should be allocated so that value added by the last unit is the same in all cases. This generalization is popularly called the equi-marginal.
Let us assume a case in which the firm has 100 unit of labour at its disposal. And the firm is involved in five activities viz., А, В, C, D and E. The firm can increase any one of these activities by employing more labour but only at the cost i.e., sacrifice of other activities.
An optimum allocation cannot be achieved if the value of the marginal product is greater in one activity than in another. It would be, therefore, profitable to shift labour from low marginal value activity to high marginal value activity, thus increasing the total value of all products taken together.