three-sector theory

An alternative analysis of economies, the three-sector theory, subdivides them into:

In modern economies, these phase precedences are somewhat differently expressed by the three-sector theory.

At the top level, industry is often classified according to the three-sector theory into sectors: primary or extractive, secondary or manufacturing, and tertiary or services.

Perhaps his most notable contribution was to investigate economic development in terms of the sequential dominance of different sectors of the economy: the primary, secondary and tertiary sectors (three-sector theory).