Differences in size of primary, secondary and tertiary sectors

Economic Development: Comparing Primary, Secondary and Tertiary Sectors Across Countries

Exam Tip 🚀

When answering questions about sector sizes, remember to:

  1. Identify the primary, secondary, tertiary sectors.

  2. Give a real‑world example for each sector.

  3. Use the formula Sector Share = (Sector GDP ÷ Total GDP) × 100% to calculate percentages.

1. What Are the Three Sectors? 📚

Think of the economy as a three‑layer cake:

  • Primary sector – the base layer, where raw materials are extracted or grown (e.g., farming, mining).

  • Secondary sector – the middle layer, where those raw materials are turned into finished goods (e.g., factories, construction).

  • Tertiary sector – the top layer, where services are delivered (e.g., banking, tourism).

Analogy: Imagine a pizza. The dough is the primary sector, the sauce and cheese are the secondary sector, and the toppings plus delivery service are the tertiary sector.

2. Measuring Sector Size 📊

Sector size can be measured by its contribution to GDP or by the share of employment it provides.

Formula for GDP share:

Sector Share = (Sector GDP ÷ Total GDP) × 100%

Example: If the primary sector contributes \$200\$ billion to a \$1,000\$ billion GDP, its share is:

(200 ÷ 1000) × 100% = 20%

3. Sector Size in Developing vs. Developed Countries 🌍

CountryPrimary SectorSecondary SectorTertiary Sector
Kenya (Developing)32%28%40%
Germany (Developed)3%38%59%

Key Observation: In developing economies, the primary sector is larger, while in developed economies the tertiary sector dominates.

Key Takeaway 📌

As a country develops, its economy typically shifts from a primary‑heavy structure to a tertiary‑heavy structure. This transition reflects increased industrialisation and a growing service sector.

4. Quick Quiz for You 🤔

  1. Which sector would you find most of the jobs in a small fishing village?

  2. In a tech hub like Singapore, which sector is likely to be the largest?

  3. Calculate the secondary sector share if it contributes \$450\$ billion to a \$1,200\$ billion GDP.

Answer Key:

  • Primary sector – fishing.

  • Tertiary sector – services (finance, IT).

  • Secondary share = (450 ÷ 1200) × 100% = 37.5%

Exam Tip 📝

When you see a question about sector sizes, start by identifying the country’s level of development, then match the sector shares to the typical pattern (primary > secondary > tertiary in developing economies, and the reverse in developed economies).