Social stratification refers to the hierarchical ranking of social groups based on factors like wealth, income, occupation and education. Education plays a key role in both social stratification and social mobility. It determines social placement and can reinforce stratification by helping maintain intergenerational status, or promote mobility by allowing people to change their social position. Social mobility refers to movement between social classes, and can be vertical (changing status levels) or horizontal (changing positions within the same status). Education is a fundamental factor for development and can facilitate both economic growth and social mobility.