stratification

Meaning: Stratification is the ranking of people into layers of a hierarchy based on unequal access to wealth, power and prestige. It is a feature of social structure, so rankings persist across generations and shape life chances such as education and health. A caste system is closed: position is ascribed at birth and mobility is very limited. A class system is more open: position depends partly on achieved status, so social mobility is possible, either intergenerational (child versus parent) or intragenerational (within one lifetime).

On the MCAT: Passages describe income gaps or educational differences and ask which theory fits. Functionalism (Davis-Moore) holds that unequal rewards motivate people to fill demanding, important roles. Conflict theory holds that powerful groups shape institutions to protect their advantage. Expect questions on ascribed versus achieved status, types of mobility, and the Gini coefficient, which runs from 0 (perfect equality) to 1 (maximal inequality).

Common confusion: Stratification is not the same as inequality or class. Inequality is the unequal distribution itself; stratification is the structured, lasting system that ranks groups, and class is one form it takes. Also keep wealth (assets minus debts) separate from income (money earned per period).