Social stratification involves hierarchical differences and inequali­ties. In the money-based stratification system in the United States, wealth and income are the main determinants of social class. Social stratification also involves status and power.

Since the 1970s, the United States has experienced increasing income inequality, but the greatest economic disparities are due to differences in wealth. People with great wealth often have high social class positions, status, and power and can usually pass these on to future generations. In contrast, those who are poor find it impossible to amass wealth and therefore have little or nothing to pass on to future generations. Members of minor­ity groups, women, and children are overrepresented among the poor. The middle class in the United States has declined in recent decades. While many individuals in the United States desire upward mobility, it is difficult to achieve, and some even experience downward mobility.

Structural-functional theories of stratification argue that a system of stratification is needed in order for society to func­tion properly. Conflict theorists challenge the idea that a high degree of stratification is necessary and that positions at the higher end of the stratification system are always more impor­tant than those at the lower end. Symbolic interactionists view stratification as a process or set of interactions among people in different positions.

In terms of consumption, those in the higher classes can afford expensive items that those in the lower classes cannot. Elites use their patterns of consumption to distinguish themselves, sometimes conspicuously, from those beneath them.

Global stratification involves hierarchical differences and inequal­ities between parts of the world, as well as between the individu­als who live in them. Global stratification can be conceptualized in various ways—in terms of the oppression and domination of the Global South by the Global North; in terms of differences among upper-, middle-, and low-income countries; or in terms of differences between the richest and poorest areas of the world, the latter of which encompass the world’s “bottom billion” individuals.

Global inequalities can take many forms. There is a large and per­sistent global digital divide, with widely varying levels of access to and use of the Internet. Differences in wealth also lead to global health inequalities, including vastly different life expectancies, levels of nutrition, and disease rates. Furthermore, gender strati­fication exists throughout the world because men have greater access to employment, income, and wealth than do women.

It is possible for countries and regions to develop economically and to improve their positions within the global stratification system. Poor countries can offer the lowest wages possible (the race to the bottom) in order to attract further development. Foreign aid can help a country develop and improve social wel­fare. However, problems are associated with both strategies.

The dominant structural/functional theory of global stratification is modernization theory, which argues that technological and cultural factors explain countries’ varying levels of economic and social development. In contrast, conflict theories such as world-systems theory contend that rich countries oppress and exploit poor countries, thus keeping them poor.