In the social sciences, social stratification is any given society’s categorization of its people into rankings of socioeconomic tiers based on factors like wealth, income, social status, occupation, and power. Stratification is the relative social position of persons in a given social group, category, geographical region or other social unit. In modern Western societies, stratification is often broadly divided into three main divisions of social class: upper class, middle class, and lower class. Each of these classes can be further subdivided into smaller classes (e.g., “upper-middle”). Social strata may otherwise be formed on the basis of kinship ties or caste designations. Such social categorization is not peculiar to complex state-based societies but also found in simple tribal or feudal societies composed of nobility-to-peasant relations. Scholars debate whether the earliest hunter-gatherer groups may be defined as ‘stratified’ or if such differentials began with agriculture and widespread acts of exchange between groups. One of the ongoing issues in determining the structure of social stratification arises from the point that status inequalities between individuals are common, so it becomes a quantitative issue to determine how much social inequality qualifies as stratification. In general, the more complex the society, the more numerous the layers or strata of social differentiation.