The four sectors
Primary, secondary, tertiary, quaternary.
Primary. EXTRACTING raw materials. Farming, fishing, mining, forestry, oil/gas. Most workers in developing countries.
Secondary. MANUFACTURING — raw materials → finished goods. Car factories, textiles, food processing, steel, construction. Peaks in industrialising economies.
Tertiary. SERVICES — selling something rather than making it. Retail, healthcare, education, banking, tourism, transport, hospitality. Dominates developed economies.
Quaternary. KNOWLEDGE work. R&D, IT, biotech, finance analytics, consulting. Often grouped with tertiary in older models. Concentrated in developed economies.
Cambridge tip. Mark scheme rewards clear definitions + correct examples for each.
- Primary extracts.
- Secondary transforms.
- Tertiary serves.
- Quaternary knows.
See the full worked example for employment structures and the changing world of work →