Theories of Population
The Malthusian theory of population is the most well-known theory on population in economics. Malthus pointed out that an accelerated increase in poplation would outweigh the increase in food production. This would have an adverse impact on the development of an economy. This theory is explained in the following propositions:
1.The rate of growth of population is limited by the availability of the means of subsistence i.e. food. If the means of subsistence increase, population also increases unless it checked.
2.Population increases at a faster rate than food production. In other words, while population increases in a geometric progression, food production increases in an arithmetic progression.
3. The preventive and positive checks are the two measures to keep the population on the level with the available means of subsistence.
The first proposition states that the size of population is determined by the availability of food production. In other words, greater production can sustain a larger population. If food production does not increase to match the rate of growth of population, it will lead to poverty. The want of food would result in deaths and thereby automatically limit the population. If the food production increases, the people will tend to increase their family size. This will lead to more demand for food, so the availability of food per person will diminish. This will lead to a lower standard of living.
The second proposition states that population would increase at a geometrical progression i.e. in the ratio of 2, 4, 8, 16, 32, etc., but food production would increase at an arithmetical progression i.e. in the order of 2, 4, 6, 8, 10, etc. If population increases there will be a burden on land, which is limited; as a result there will be diminishing returns. This will lead to a decrease in the output per worker and a corresponding decrease in the availability of food per person. The imbalance between the population growth and food supply would lead to a bare subsistence of living, misery and poverty.
This imbalance is corrected by two checks namely preventive checks and positive checks.
Preventive checks are those checks applied by man to reduce the population. The preventive checks include late marriage, self-restraint and other similar measures applied by people to limit the family.
Positive checks affect population growth by increasing death rate. The positive checks on population are many and include every cause either from vice or misery which helps to shorten the life span. Common diseases, plagues, wars, famines unwholesome occupations, excess labour, exposure to the seasons, extreme poverty, bad nursing of children are a few examples for positive checks.
Malthus thus recommended that the preventive checks can be used by mankind to avoid misery or else the positive checks would come into operation. As a result, there will be a balance between population and food production. Malthusian theory is explained in the following Flow Chart.
The modern theory of optimum population brings out the relationship between changes in population and the consequent changes in per capita income. Modern economists such as Sidgwick, Cannon, Dalton and Robbins have propagated this theory.
Optimum population means the ideal population relative to the natural resources, stock of capital equipment and state of technology. There will be an ideal size of population at which per capita output (or real income per head) will be the highest.
In other words, optimum population is that level of population at which per capita output is the highest. A country is said to beunderpopulated if the population is less then the optimum and overpopulated if the population is more than the optimum.
Let us assume that the availability of natural resources, capital equipment and state of technology remain fixed in a country. The population is assumed to be small relative to these resources. When population increases, the labour force in a country also increases. As additional labour is combined with fixed amounts of these resources, the per capita output will initially rise due to greater of specialisation and more efficient use of natural and capital resources available. As population increases, a point will be reached when capital and natural resources will be fully exploited and output will be the highest.
Thus, the level of population at which the per capita output is the highest is known as optimum population. Beyond this point, if thepopulation increases, the country will become overpopulated and the per capita output will start decreasing because there are more women/men in relation to natural resources in the economy.
Thus, the given amount of capital and natural resources have to be shared among a larger number of workers resulting in smaller amount of equipment, materials and natural resources available per person to work with. Thus, the average productivity declines. With the fall in the output per head, per capita income and standard of living of the people also decline. Overpopulation leads to a low standard of living, disguised unemployment and food shortage.
Both underpopulation and overpopulation have shortcomings. It is optimum population with the highest per capita output which is best suited for a country. This is explained in Figure.
In the figure, size of population is measured on the X-axis and output per capita on the Y-axis. It is clear that as population increases, output per capita also increases till OM. At OP level of population, output per capita is the highest and is equal to MP. If population increases beyond the level OP, then per capita output will fall. Therefore OP is the optimum population. If the actual population is less than OP, a country is said to be underpopulated and if it is more then OP, it is overpopulated.
The following formula measures whether population at a point of time is optimum or not
M = A-O/ O
M = Maladjustment in level of output
A =Actual population
O =Optimum population
If 'M' is zero, then the total population is equal to optimum population
If 'M' is positive, the total population is more then the optimum population.
If 'M' is negative, the total population is less then the optimum population
The demographic transition brings out the relationship between fertility and motility, i.e. between the birth rate and the death rate. Birth rate refers to the number of births occurring per 1000 in a year. Death rate refers to the number of deaths occurring per 1000 in a year. This theory explains the changes in these rates as a consequence of economic development. This theory points out that there are three distinct stages of population growth.
In the first stage, the country is backward and less developed. Agriculture will be the main occupation of the people and primitive mode of cultivation will be used. The standard of living of the people will be low. This stage is characterised by high birth rate and high death rate. The high death rate is due to poor diets, improper sanitation and lack of proper medical facilities. Birth rate is high on account of widespread illiteracy, ignorance of family planning techniques, early marriages, social beliefs, customs and attitudes of the people. In this stage, the rate of growth of population is not high since high birth rate is offset by the high death rate and the population growth stagnates.
As a country advances, it might result in increase in industrial activity, creating more employment opportunities. This will raise the national and per capita income of the people, thereby increasing their standard of living. The economy reaches the second stage of high birth rate and low death rate. The advancement in science and technology will result in the availability of better medical facilities.
The eradication of many epidemics and dangerous diseases and better sanitary conditions reduce the incidence of disease and death. The birth rate still remains high due to the resistance to change, and the long established customs and beliefs. Thus there is an imbalance between high birth rate and low death rate resulting in high population growth, and the country witnesses population explosion
Economic development leads to change in the structure of the economy from an agrarian to a partially industrialised one. With the increase in industrialisation, people migrate from rural to urban areas, and there is a change in the attitude of the people. With the spread of education, people prefer small families in order to increase the standard of living. Thus the birth rate is reduced.
Implementation of better medical facilities, control of disease and public sanitation result in low death rate. During this third stage of low birth and death rates, the growth of population tends to be stable. Almost all countries have passed through these three stages (demographic transition) of population growth. The three stages of demographic transition are shown in Figure 2.2.
The term 'Census' can be defined as the process of collecting, compiling, evaluating, analysing and publishing the demographic economic and social data relating to all persons in a country or a well-delimited part of a country at a specified time.
Census of population in India was taken in 1872 and then in 1881. From then onwards, the census is taken once in 10 years. The latest census was taken in 2001. Census is very important to know (1) the rate of growth of population (2) the changes in the distribution of the population.