What is the difference between inequality and social mobility?

Inequality describes how unevenly income, wealth, or status are distributed within a society at a given time. Social mobility describes how easily individuals or families move between positions in that distribution, including across generations. A society can be highly unequal yet have high mobility, or vice versa.

What is the Kuznets curve?

The Kuznets curve is a hypothesis, proposed by Simon Kuznets, that economic inequality first rises and then falls as a country develops, tracing an inverted U. Later long-run data, especially that compiled by Piketty and others, has challenged the idea that such a decline is automatic.

Social Mobility and Inequality

This topic studies the historical distribution of income, wealth, and opportunity—how unequal past societies were, how that inequality changed, and how much people moved between social positions.

Definition

The historical study of the distribution of income, wealth, and opportunity, and of the extent to which individuals and families move between social and economic positions over time.

Scope

This topic covers the long-run history of economic and social inequality and of social mobility: how the distribution of income and wealth has varied across societies and over time, what has driven inequality up or down, and how readily individuals and families have moved between social ranks. It examines the measurement of inequality from historical sources, theories linking it to growth, capital, and institutions, and debates over the persistence of advantage across generations. The treatment is descriptive and analytical, surveying scholarly findings rather than prescribing distributive policy.

Core questions

How unequal were past societies, and how did inequality change over time?
What forces drove inequality up or compressed it?
How much social mobility existed, and how persistent was advantage across generations?
How can historians measure inequality and mobility from surviving records?

Key theories

Capital and the long-run dynamics of inequality: Piketty's thesis that when the rate of return on capital exceeds the rate of economic growth, wealth tends to concentrate, so that high inequality is the historical norm absent shocks or strong policy.
Violence as a leveller of inequality: Scheidel's argument that major reductions in inequality have historically been driven chiefly by catastrophic shocks—mass-mobilization war, revolution, state collapse, and pandemics—rather than by peaceful reform.
Persistence of social status: Clark's surname-based studies suggesting that underlying social mobility is much slower than conventional single-generation measures imply, with family status persisting strongly over many generations.

History

The historical study of inequality has roots in classical political economy and in Simon Kuznets's mid-twentieth-century hypothesis that inequality first rises then falls with development. From the 2000s, the assembly of long-run data on top incomes and wealth, associated with Thomas Piketty and collaborators, transformed the field, while Lindert and Williamson reconstructed American inequality over three centuries. Recent work by Walter Scheidel and Gregory Clark has reframed debates about the drivers of inequality and the persistence of social status.

Debates

How mobile have societies actually been?: Scholars debate whether conventional measures overstate social mobility, with Gregory Clark's surname studies suggesting that status is far stickier across generations than standard parent-child correlations imply, against accounts emphasizing greater openness.

Key figures

Thomas Piketty
Peter Lindert
Jeffrey Williamson
Gregory Clark
Walter Scheidel

Seminal works

piketty2014
scheidel2017
clark2014
lindertwilliamson2016

Frequently asked questions

What is the difference between inequality and social mobility?: Inequality describes how unevenly income, wealth, or status are distributed within a society at a given time. Social mobility describes how easily individuals or families move between positions in that distribution, including across generations. A society can be highly unequal yet have high mobility, or vice versa.
What is the Kuznets curve?: The Kuznets curve is a hypothesis, proposed by Simon Kuznets, that economic inequality first rises and then falls as a country develops, tracing an inverted U. Later long-run data, especially that compiled by Piketty and others, has challenged the idea that such a decline is automatic.