AP Human Geography – Demographic Transition Model (DTM) and Epidemiological Transition Model

AP Human Geography – Demographic Transition Model (DTM) and Epidemiological Transition Model

AP Human Geography Study Guide: Demographic Transition Model (DTM) & Epidemiological Transition Model

What This Is

The Demographic Transition Model (DTM) explains how a country’s population changes as it develops economically, shifting from high birth and death rates to low ones. The Epidemiological Transition Model describes how causes of death change as societies modernize (e.g., from infectious diseases to chronic illnesses). These models are core to AP HuG—expect multiple-choice questions and FRQs on interpreting graphs, comparing countries, and explaining population trends.
Example: Sweden’s population shifted from high birth/death rates in the 1700s (Stage 1) to low rates today (Stage 4), while Nigeria remains in Stage 2 with rapid growth.

Key Terms & Concepts

• Demographic Transition Model (DTM): A 5-stage model showing how birth rates (CBR) and death rates (CDR) change as a country industrializes.
• Stage 1 (High Stationary): High CBR/CDR, low growth (e.g., pre-industrial societies like medieval Europe).
• Stage 2 (Early Expanding): High CBR, falling CDR, rapid growth (e.g., Nigeria, Afghanistan today).
• Stage 3 (Late Expanding): Falling CBR, low CDR, slowing growth (e.g., Mexico, India).
• Stage 4 (Low Stationary): Low CBR/CDR, stable population (e.g., U.S., France).

• Stage 5 (Declining): CBR < CDR, population decline (e.g., Japan, Germany).

• Epidemiological Transition Model: Shifts in causes of death as countries develop:

• Stage 1 (Pestilence & Famine): Infectious diseases (e.g., Black Death in Europe).
• Stage 2 (Receding Pandemics): Improved sanitation reduces infectious diseases (e.g., 19th-century London cholera outbreaks).
• Stage 3 (Degenerative Diseases): Chronic illnesses (e.g., heart disease, cancer in the U.S. today).
• Stage 4 (Delayed Degenerative Diseases): Longer lifespans but still chronic diseases (e.g., Japan’s aging population).

• Stage 5 (Reemerging Infections): Antibiotic-resistant diseases (e.g., COVID-19, Ebola).

• Crude Birth Rate (CBR): Number of live births per 1,000 people per year.

• Crude Death Rate (CDR): Number of deaths per 1,000 people per year.
• Natural Increase Rate (NIR): CBR – CDR (expressed as a percentage). Formula: (CBR – CDR) / 10.
• Total Fertility Rate (TFR): Average number of children a woman will have in her lifetime (e.g., TFR = 2.1 is replacement level).
• Infant Mortality Rate (IMR): Number of infant deaths per 1,000 live births (high in Stage 1, low in Stage 4).
• Dependency Ratio: Ratio of dependents (under 15, over 65) to working-age population (15–64). Formula: (# dependents / # working-age) × 100.
• Malthusian Theory: Thomas Malthus argued population grows exponentially while food supply grows linearly, leading to famine (criticized for ignoring technology).
• Neo-Malthusians: Modern supporters who warn of resource depletion (e.g., water scarcity, climate change).
• Anti-Malthusians: Optimists who believe technology and innovation will solve resource shortages (e.g., Green Revolution).

Step-by-Step: How to Analyze a DTM Graph on the AP Exam

1. Identify the Stage: Look at CBR/CDR trends (e.g., high CBR + falling CDR = Stage 2).
2. Calculate NIR: Subtract CDR from CBR, divide by 10 for percentage (e.g., CBR 30 – CDR 10 = 20 → NIR = 2%).
3. Compare Countries: Stage 2 countries (e.g., Nigeria) have young populations; Stage 4 (e.g., Japan) have aging populations.
4. Link to Development: Stage 2 = less developed; Stage 4 = more developed.
5. Predict Future Trends: If CBR > CDR, population grows; if CBR < CDR (Stage 5), population declines.
6. Connect to Epidemiological Transition: Stage 2 = infectious diseases; Stage 4 = chronic diseases.

Common Mistakes

• Mistake: Confusing Stage 2 and Stage 3 (both have population growth, but Stage 3 growth slows).

• Correction: Stage 2 has rapid growth (high CBR, falling CDR); Stage 3 has slowing growth (falling CBR, low CDR).

• Mistake: Assuming all countries follow the DTM in order (e.g., some skip stages due to war or policy).

• Correction: The DTM is a model, not a law—real-world exceptions exist (e.g., China’s one-child policy accelerated its transition).

• Mistake: Forgetting Stage 5 (declining population) exists.

• Correction: Stage 5 is a modern addition—countries like Japan and Germany have CBR < CDR.

• Mistake: Mixing up CBR/CDR with TFR (CBR is per 1,000 people; TFR is per woman).

• Correction: CBR = births per 1,000; TFR = average births per woman.

• Mistake: Ignoring cultural factors (e.g., religion, gender roles) in fertility rates.

• Correction: High TFR in Stage 2 isn’t just about development—it’s also about lack of women’s education and agricultural economies needing child labor.

AP Exam Insights

• Tricky Distinction: DTM vs. Epidemiological Transition—DTM focuses on population growth; epidemiological transition focuses on causes of death.
• FRQ Trap: Expect a Stage 2 vs. Stage 4 comparison (e.g., “Explain why Nigeria’s population pyramid is wide at the base while Japan’s is top-heavy”).
• Multiple-Choice Trap: Questions may ask about Stage 5 (e.g., “Which country is most likely in Stage 5?” → Japan, not Nigeria).
• Graph Interpretation: You’ll see population pyramids—Stage 2 = pyramid shape; Stage 4 = rectangle/urn shape.
• Policy Connections: Be ready to link DTM stages to government policies (e.g., China’s one-child policy = Stage 3; Sweden’s pro-natalist policies = Stage 4).

Quick Check Questions

1. Multiple Choice: Which of the following is characteristic of a country in Stage 3 of the DTM?
   a) High birth rates and high death rates
   b) High birth rates and low death rates
   c) Declining birth rates and low death rates
   d) Low birth rates and rising death rates
   Answer: c) Declining birth rates and low death rates (Stage 3 has slowing growth).

2. Short FRQ: Explain how the Epidemiological Transition Model applies to the U.S. today. Identify the stage and describe the primary causes of death.
   Answer: The U.S. is in Stage 4 (Delayed Degenerative Diseases), where chronic illnesses (heart disease, cancer) are the leading causes of death due to aging populations and lifestyle factors.

3. Multiple Choice: A country with a high dependency ratio and low TFR is most likely in which DTM stage?
   a) Stage 1
   b) Stage 2
   c) Stage 4
   d) Stage 5
   Answer: d) Stage 5 (aging population + low birth rates = high dependency ratio).

Last-Minute Cram Sheet

1. Stage 1: High CBR/CDR, no growth (e.g., pre-industrial tribes).
2. Stage 2: High CBR, falling CDR, rapid growth (e.g., Nigeria, Afghanistan).
3. Stage 3: Falling CBR, low CDR, slowing growth (e.g., Mexico, India).
4. Stage 4: Low CBR/CDR, stable population (e.g., U.S., France).
5. Stage 5: CBR < CDR, population decline (e.g., Japan, Germany).
6. Epidemiological Stage 1: Infectious diseases (e.g., Black Death).
7. Epidemiological Stage 3: Chronic diseases (e.g., heart disease, cancer).
8. NIR Formula: (CBR – CDR) / 10 (e.g., CBR 20 – CDR 10 = 1% NIR).
9. ⚠️ TFR = 2.1 is replacement level (below = population decline).
10. ⚠️ Stage 2 countries have young populations; Stage 4 have aging populations.