Concept of Optimum Population: Optimum population has been defined as that size of population enabling per capita output of the maximum orders accompanied by the highest possible standards of living under a given set of economic and technological conditions. Therefore, optimum population lies between two extremes, i.e., overpopulation and under-population, although the size of optimum population is not sacrosanct. It is a theoretically perfect situation difficult to estimate or define. The Penguin Dictionary of Geography characterises optimum population as a situation when the number of individuals can be accommodated in an area to the maximum advantage of each individual. Thus optimum population yields highest quality of life, which means each person has access to adequate food, water, energy and air of highest quality, adequate medical care, recreational facilities and cultural outlets. In other words, optimum population permits the highest per capita output; therefore the marginal productivity exceeds the average productivity whereby the rates of growth of total production are the highest. hp://www.yourarclelibrary.com/essay/overpopulaon-under-populaon-opmum-populaon Assumptions: The optimum theory is based on two important assumptions: ADVERTISEMENTS: 1. The proportion of working population to total population remains constant as the population of the country increases. 2. As the population of a country increases, the natural resources, the capital stock and state of technology remain unchanged. Diagrammatic Representation of the Theory : In the diagram I volume of population is shown along OX axis and income per head along OY-axis. OS is the income per head which gives only subsistence wage rate to the population. This level of wages puts the minimum limit to the income per head. The subsistence income per head can prevail with two levels of population: 1. When population is too small to exploit the country’s resources with maximum efficiency. This is the level of OA population.