Optimum Population Theory

Optimum Population Theory

The relationship between population and resources is a central theme in population geography and economics. The Optimum Population Theory attempts to determine the most desirable size of population that allows maximum economic welfare with the available resources and technology.

This theory emerged as a reaction to Malthusian pessimism, which viewed population growth as necessarily leading to poverty and famine. Instead, the Optimum Theory argues that neither too small nor too large a population is desirable – rather, there exists an optimum level that maximises per capita income and social welfare.

Historical Evolution of the Optimum Population Theory

1. Early Philosophical Roots – Confucius (551–479 BCE)

• The origin of the idea of optimum population can be traced back to Confucius, the ancient Chinese philosopher.
• He emphasized moderation and balance in population size, linking it with social stability and economic welfare.
• Confucius warned against excessive population growth, noting:
  • “Excessive growth may reduce output per worker, repress levels of living for the masses, and engender strife.”
• This reflects an early recognition of the relationship between population size and standard of living, forming a philosophical foundation for the concept of population balance.

2. Early Modern Precursors – Richard Cantillon (18th Century)

• The term “Optimum Population” was first used by Richard Cantillon in the 18th century.
• Cantillon viewed population as an economic factor — asserting that the most desirable size of population is the one that best utilizes available natural and capital resources, ensuring maximum standard of living.
• His ideas laid the groundwork for later economists who sought to formalize this balance between population, resources, and welfare.

3. 19th Century Development – Karl Winkelblech (1810–1865)

• A German economist and professor, Karl Winkelblech, contributed to early population theory by classifying nations based on their population size relative to resources.
• He categorized nations into three groups:
  1. Under-populated nations – too few people to fully utilize resources.
  2. Over-populated nations – too many people exerting pressure on resources.
  3. Normal (Optimum) nations – balanced population with highest possible productivity.
• This categorization anticipated the core structure of the Optimum Population Theory that would be developed formally in the 20th century.

4. Formal Formulation – Edwin Cannan (1924)

• The Optimum Population Theory was formally propounded by Edwin Cannan in his book “Wealth” (1924).
• Cannan rejected Malthus’s pessimistic view that population growth inevitably leads to misery.
• He proposed that an increase in population could be beneficial up to a certain point, as it promotes specialization, division of labour, and efficient resource use — but beyond that, further growth leads to declining returns.
• Thus, the optimum population is achieved when per capita income is maximized, ensuring the best utilization of all available means of production.

5. Refinement and Popularization – Robbins, Carr-Saunders, and Dalton (20th Century)

(a) Lionel Robbins

• Robbins defined the concept as:
  • “The population which just makes the maximum returns possible is the optimum population or the best possible population.”
• His emphasis was on economic efficiency — the most productive balance between labour and resources.

(b) Carr-Saunders

• Carr-Saunders expanded the concept beyond economics to include social welfare, defining it as:
  • “That population which produces maximum economic welfare.”
• He thus introduced the idea that optimum population should not only yield maximum output but also ensure the overall well-being of society.

(c) Dalton

• Hugh Dalton provided the most scientific and realistic explanation.
• He defined optimum population as:
  • “That which gives the maximum income per head.”
• Dalton’s formulation linked the concept directly to national income and living standards, making it measurable in economic terms.
• He viewed the optimum population as dynamic, varying with changes in resources, technology, and capital.

Assumptions / Postulations of the Optimum Population Theory

• The Optimum Population Theory is based on several simplifying assumptions. These assumptions were necessary to develop a theoretical relationship between population size and economic welfare (or per capita income). However, they also limit the applicability of the theory in real-world dynamic economies.
• Fixed Natural Resources
  • The theory assumes that the natural resources of a country are fixed at a given point of time.
  • That means the availability of land, minerals, water, and other natural endowments does not change immediately.
  • However, it is accepted that these resources may change gradually over time due to exploration, conservation, or depletion.
  • Hence, the theory initially treats resource availability as constant to isolate the impact of population on income.
• No Change in Techniques of Production
  • It assumes that methods and techniques of production remain constant.
  • There is no technological progress or innovation that could alter productivity levels.
  • This is important because any improvement in technology could shift the point of optimum population, making it dynamic rather than fixed.
• Constant Stock of Capital
  • The amount of capital available for production (machinery, tools, infrastructure, etc.) is assumed to remain unchanged.
  • Therefore, any change in total output is attributed only to changes in population, not to changes in capital formation.
  • This allows economists to clearly observe how population affects per capita income under a fixed resource-capital framework.
• Unchanged Habits and Tastes of People
  • The preferences, consumption habits, and tastes of the population are assumed to remain constant.
  • This ensures that the pattern of demand does not alter economic structure, allowing a pure analysis of population-resource relationships.
  • In real life, however, rising incomes often change consumption patterns, which can influence the demand for labour and resources.
• Constant Ratio of Working Population to Total Population
  • It is assumed that the proportion of working population (labour force) to total population remains unchanged, even when population grows.
  • This means the dependency ratio stays fixed — so any increase in total population brings a proportional increase in the workforce.
  • In practice, demographic variations (like aging, fertility rate, or gender participation) often change this ratio.
• Fixed Working Hours
  • The theory assumes that the working hours of labour remain constant.
  • There is no variation in the duration or intensity of labour effort with population changes.
  • This helps maintain a controlled environment for analyzing output and per capita income.
• Constant Mode of Business Organisation
  • The structure and methods of business organization (like production management, labour relations, and entrepreneurship) are assumed to be unchanged.
  • This ensures that any observed change in output or income results purely from population variation, not from managerial or organizational efficiency.

Optimum Population Theory

• The Optimum Population Theory seeks to determine the ideal size of population that allows a country to make the best possible use of its available resources—both natural and capital—to achieve the maximum possible income per capita (or standard of living).
• It represents the most desirable balance between population and resources, ensuring economic efficiency and welfare.
• The Optimum Population is that ideal size of population which, given the available resources, capital, and technology, yields the maximum per capita income.
• In other words, it is the population level at which economic welfare is maximized.
• Any deviation—either increase or decrease—from this level reduces average income and welfare.
• Theoretical Explanation:
  • At a given time, assuming constant natural resources, capital stock, and production techniques, there exists a definite population size that ensures highest per capita output.
  • When the population is below this level, resources remain underutilized; when it exceeds this level, resources get overstrained.
• Relationship between Population and Per Capita Income
  • (a) Under-Population
    • When the population is less than the optimum level, an increase in population leads to higher per capita income.
    • This happens because more workers help in better utilization of natural and capital resources, increasing total and per capita output.
    • Hence, the country is said to be under-populated, and population growth is desirable until the optimum level is reached.
  • (b) Optimum Population
    • At this stage, the per capita income reaches its maximum.
    • Resources and labour are in perfect balance—neither underused nor overused.
    • The average product of labour (output per worker) is the highest at this point.
  • (c) Over-Population
    • Beyond the optimum level, any further increase in population results in decline of per capita income.
    • This is because the available land and capital become inadequate, leading to diminishing returns on labour.
    • The country becomes over-populated, and economic welfare declines.
• Dynamic Nature of Optimum Population
  • The optimum level of population is not a fixed number; it varies with changes in technology, capital, and resources.
  • For instance:
    • Technological Progress → raises productivity → shifts the optimum population upward (the country can now support more people at a higher income level).
    • Increase in Natural Resources or Capital Stock → increases carrying capacity → moves the optimum point higher.
    • Depletion of Resources or Technological Backwardness → lowers the optimum level.
• Theoretical Curve Explanation (Descriptive Form)
  • If we plot population size on the X-axis and per capita income on the Y-axis, the relationship forms a bell-shaped curve.
  • The curve rises initially (as population increases from low levels), reaches a peak at the optimum point, and then falls (as overpopulation sets in).
  • The peak represents the Optimum Population Point, where per capita income is maximum.

Dalton’s Formula

• Economist Hugh Dalton tried to make the Optimum Population Theory more measurable by introducing a simple mathematical expression to show how far a country’s actual population deviates from its ideal (optimum) level.
• He called this deviation maladjustment (M) — representing the degree of imbalance between actual population (A) and optimum population (O).
• The formula is expressed as:
  M = (A – O) / O
• Interpretation:
  • If M = 0 → The population is exactly optimum; resources and population are perfectly balanced, yielding the highest per capita income.
  • If M > 0 → The actual population exceeds the optimum, meaning the country is overpopulated — pressure on land, food, and employment increases, reducing per capita income.
  • If M < 0 → The actual population is below the optimum, meaning the country is underpopulated — resources remain underutilized, and per capita income can rise if the population increases.
• Example:
  • Suppose the optimum population of a country is 100 million, but the actual population is 120 million.
    Then, M = (120 – 100) / 100 = +0.2 → indicates 20% overpopulation.
  • Conversely, if the actual population is 80 million, then M = (80 – 100) / 100 = –0.2 → indicates 20% underpopulation.
• This formula gives a simple quantitative way to assess whether a country’s population is aligned with its economic potential.

P. Sengupta’s Formula

• Indian economist P. Sengupta proposed a formula to measure population balance specifically in agrarian economies like India, where land is the dominant resource base.
• His formula focuses on the carrying capacity of land resources and how much rural population can be sustained without overexploitation.
• Formula:
  I = (P₁ – P) / A where,
  • I = Index of population balance
  • P₁ = Rural population that can be supported by available land and resources
  • P = Actual rural population
  • A = Total area of the region
• Interpretation:
  • If I > 0 → The area is underpopulated (land can support more people).
  • If I < 0 → The area is overpopulated (population exceeds land’s capacity).
  • If I = 0 → The area is in a state of balance — rural population matches land potential.
• Applicability in India:
  • Since agriculture is the mainstay for a large portion of India’s population, this index helps identify regions of overpopulation (e.g., Bihar, Uttar Pradesh, West Bengal) and underpopulation (e.g., Rajasthan desert, parts of Madhya Pradesh).
  • Useful for regional planning, resource management, and population control policies in rural India.

Examples of Optimum Population

• The concept of optimum population does not depend merely on population size or density, but on how effectively a country can utilize its available resources to achieve the highest possible standard of living. The same number of people can be overpopulated in one country and underpopulated in another, depending on economic and technological factors.
• United States of America (USA):
  • Although the USA is the third most populous country in the world, it is not overpopulated.
  • This is because of its abundant natural resources, high level of technology, capital investment, and efficient economic organization, which together enable a very high per capita income.
  • Thus, the USA’s population is considered near the optimum level, as resources are effectively utilized to sustain high living standards.
• Singapore:
  • Singapore has an extremely high population density, yet it is not overpopulated.
  • Through efficient governance, technological advancement, global trade, and strategic economic planning, it has managed to achieve very high per capita income and economic stability.
  • Hence, despite limited land and natural resources, optimum utilization of human and capital resources makes its population optimum or even economically advantageous.
• Saharan Countries (e.g., Niger, Chad, Mali):
  • These countries have low population density, but due to scarce resources, poor technology, and low productivity, they are overpopulated in the relative sense.
  • The population exceeds the carrying capacity of available resources, leading to poverty, malnutrition, and low living standards.
  • Thus, they are overpopulated despite small population size, showing that overpopulation is a relative economic concept, not merely numerical.
• Australia and Canada:
  • Both countries have vast land areas and rich natural resources, but relatively small populations.
  • They are examples of underpopulated nations, as their resources could support a larger population without lowering per capita income.
  • With more people and efficient technology, they could increase productivity and approach the optimum population level.

Superiority over Malthusian Theory

The Optimum Population Theory holds significant advantages over the traditional Malthusian Theory of Population, particularly in its practical applicability and economic realism.

1. Universally Applicable:
   • Unlike Malthus’s theory, which mainly applied to underdeveloped or agrarian societies, the Optimum Population Theory is relevant to all countries, regardless of their level of economic development.
   • It considers both developed and developing nations, recognizing that even rich countries can face underpopulation issues.
2. Broader Scope:
   • While Malthus focused only on the relationship between population and food supply, the optimum theory takes into account all types of resources — natural, human, and capital — and relates population to the overall national economy (agriculture, industry, and services).
3. Dynamic Nature:
   • The theory recognizes that the optimum level of population is not static.
   • With improvements in technology, education, skill development, and capital formation, a country’s capacity to support more people can increase over time, shifting the optimum level upward.
4. Economic and Realistic Approach:
   • Unlike the pessimistic outlook of Malthus, who predicted misery and starvation, the optimum theory presents an optimistic and progressive view.
   • It focuses on achieving maximum economic welfare and higher per capita income, rather than preventing population growth through checks and balances.

Critical Analysis

Although superior to the Malthusian theory, the Optimum Population Theory has certain conceptual and practical limitations:

1. No Empirical Evidence of Optimum Level:
   • No country has been able to determine or achieve its exact optimum population.
   • The concept remains largely theoretical and cannot be precisely measured.
2. Measurement Difficulties:
   • It is extremely difficult to quantify the exact level of population that would yield maximum per capita income, since this depends on numerous changing factors like resources, technology, and labour efficiency.
3. Problem of Measuring Per Capita Income:
   • The accuracy of per capita income as an indicator of welfare is debatable, as it does not account for inequalities, informal sectors, or non-monetary aspects of wellbeing.
4. Neglect of Income Distribution:
   • The theory assumes that increased per capita income benefits all, but ignores disparities in income distribution.
   • A country may have a high per capita income but still suffer from inequality and poverty.
5. Optimum Level Not Fixed:
   • The optimum population level is constantly changing with variations in technology, resource base, and capital stock.
   • Hence, it is difficult to determine a stable point of equilibrium.
6. Ignores Social and Institutional Factors:
   • The theory focuses mainly on economic and quantitative aspects, neglecting cultural, social, and institutional variables that influence population size and productivity.
7. Limited Policy Application:
   • Governments find it difficult to formulate population policies based on this theory, since the optimum level cannot be clearly identified or targeted.
8. No Explanation for Population Growth Determinants:
   • The theory does not analyze the causes or determinants of population growth such as fertility, mortality, and migration — key components studied in demographic theories.

Also Read: Ackerman’s Classification