social stratification

Meaning: Social stratification is a society's system of ranking people into layers, or strata, with unequal access to wealth, income, power, prestige and education. The ranking is built into institutions and often carries across generations. A caste system assigns ascribed status at birth with very little mobility. A class system rests more on achieved status and allows more mobility, though barriers remain.

Two accounts explain it. Functionalists (the Davis-Moore thesis) say unequal rewards motivate talented people to fill important positions. Conflict theorists say it comes from competition for scarce resources and lets dominant groups protect their advantage.

On the MCAT: Passages give income, education or occupation data and ask you to classify a system as caste or class, name the type of mobility (vertical or horizontal; intergenerational, child versus parent, or intragenerational, within one lifetime), or pick the theory that best explains the pattern. Weber's class, status and power dimensions also appear.

Common confusion: Stratification is the ranking system itself, not the movement within it, which is social mobility. The functionalist account does not claim the system is fair. It explains a function, while conflict theory asks who benefits.