Module 10: The Demographic Transition Model
MODULE 10: The Demographic Transition Model
LEARNING GOALS
10-1 Explain how birth and death rates change over time.
10-2 Discuss whether the demographic transition model still applies today.
10-3 Explain the epidemiological transition model.
DEMOGRAPHIC TRANSITION MODEL
Overview
The human population has experienced considerable growth over time, accompanied by changes in birth and death rates.
The Demographic Transition Model (DTM) summarizes how these rates change over time, originally based on experiences in the United States and European countries but may not apply universally to all world regions.
A related concept is the epidemiological transition, which addresses health and disease patterns over time.
10-1: How do birth and death rates change over time?
Scholars observe regular patterns in how birth and death rates evolve as a country develops.
Preindustrial Societies
High Birth and Death Rates: Both rates were high, leading to minimal population growth.
Economic Context: Farming societies relied on high birth rates to sustain family labor forces.
Health Context: Poor nutrition, low public health, and limited health care for the young contributed to high death rates.
Industrial Era Changes
Late 18th Century Onset: Advances in medicine, diet, sanitation, and vaccination led to significant drops in death rates.
Life Expectancy Improvement: Increased from an average of 35 years in the 18th century to 75 years or more today.
Birth Rates Response: Birth rates fell more slowly, resulting in a surge in population as fertility exceeded mortality.
Relationships Between Rates and Economic Development
Theory of the DTM: Incorporates the relationship between crude birth rate (CBR) and crude death rate (CDR) as countries transition from preindustrial to industrialized societies.
Death rates generally decline more rapidly than birth rates, creating an interim phase of rapid population growth.
Stages of the Demographic Transition Model
The DTM consists of five stages:
1. High Stationary Stage:
Characteristics: High birth and death rates stabilize population growth.
Fluctuations in total population are common.
No current country is at this stage.
2. Early Expanding Stage:
Characteristics: Death rates drop rapidly, leading to fast population growth.
Current examples: Some sub-Saharan countries.
3. Late Expanding Stage:
Characteristics: Declining birth rates result in a slower rate of natural increase.
Economic benefit known as demographic dividend may occur.
4. Low Stationary Stage:
Characteristics: Birth and death rates are similar at low levels, with slow population growth.
Aging population becomes a concern.
Many developed countries fall into this category today.
5. Natural Decrease Stage:
Characteristics: Birth rates fall below replacement level, causing natural population decline.
Countries like Japan and Germany are examples.
Notably, immigration can still allow growth despite natural decrease.
Critiquing the Demographic Transition Model
Nonlinear Progression
The DTM suggests a specific, linear progression, but countries may revert to earlier stages due to factors like war (e.g., Angola, Afghanistan).
Examples like Oman show that increased wealth can coexist with high fertility rates.
Accelerated Progression
Some countries may skip stages, rapidly progressing through the transition (e.g., China’s one-child policy led to quick transition to stage 4).
10-2: Does the demographic transition model still apply today?
Complications arise when applying the DTM to currently industrializing countries due to variations in development experiences.
Countries in sub-Saharan Africa and South Asia show slow declines in birth rates despite rapid mortality reductions, causing accelerated population growth.
Contemporary Examples
Countries like Chad and Democratic Republic of the Congo lag in demographic transitions, while others are moving towards smaller family norms.
10-3: What is the epidemiological transition model?
The Epidemiological Transition Model was inspired by the DTM and focuses on health service improvements and their impact on disease patterns.
Proposed by Abdel Omran in 1971, it explains how modernization leads to a shift in the leading causes of death from infectious to chronic diseases.
Phases of the Epidemiological Transition
Age of Pestilence and Famine:
Characterized by high death rates from diseases like tuberculosis and smallpox; life expectancy between 20-40 years.
Age of Receding Pandemics:
Death rates decline due to improved healthcare and sanitation; life expectancy rises to about 50 years.
Increased risk of chronic diseases.
Age of Degenerative and Human-Made Diseases:
Death rates stabilize at a lower level; life expectancy can reach 70 years or more.
Major causes of death shift to chronic diseases that affect older populations.
Age of Delayed Degenerative Diseases (Optional Phase):
Reflects advances in medical technology reducing the risk of serious diseases and increasing life expectancy
Emergence of public health issues such as obesity.
Challenges and Current Issues in Epidemiological Transition
Infectious diseases are still risks in both developing and developed countries (e.g., COVID-19 and others).
MODULE 10 REVIEW
Exam Preparation Questions
10-1: The DTM indicates that countries transition from high birth/death rates to low rates as they modernize, including a fifth stage marked by natural decrease.
10-2: The DTM, based on northern Europe, may not accurately apply to today's developing nations.
10-3: The epidemiological transition discusses shifts in disease patterns alongside socioeconomic changes, with causes of death evolving from infectious to chronic diseases.
Conclusion
The DTM explains demographic transitions linked to economic changes, while the epidemiological transition model emphasizes health change over time, noting complexities and variations across different regions and nations.