The term marginal comes from the Latin, “marginalis,” and is in reference to an edge or border. In my discipline (Sociology), we trace the concept to Robert Park, who referred to the marginal man as a ...

Learn what the Marginal Propensity to Invest (MPI) means, how it’s calculated, and its impact on economic growth and investment decisions.

Marginality is commonly understood as a condition of outsideness. But it is better understood as something internal: the ways poor people are integrated into the wider society define forms and ...