Since the demise of modernization theory, social scientists have sought explanations
for persisting differences in the stratification of industrialized societies, primarily
by studying how educational and labor market institutions shape the life chances
of individuals. This approach undervalues two key features of any stratification
system: family dynamics and the welfare state. Employment changes, changes in household
composition, and changes in the employment situation of a spouse or partner can all
trigger large shifts in income and material well-being. The impact of these events
is mediated by public tax and transfer mechanisms and by private actions taken by
household members. This comparative analysis of household income dynamics in the
United States and Germany shows that variations in welfare state policy produce distinct
societal patterns of income mobility, and furthermore, shows that the relative importance
of labor market events, family change, and welfare state policies for income dynamics
depends on gender. The strong interrelationship between individual incentives and
the structure of opportunity produces an asymmetry in the long-term impact of events.
The negative effects of events that reduce income generally decay over time, while
the effects of positive events generally persist.