Measuring Social Mobility As Unpredictability.

By associating mobility with the unpredictability of social states, new measures of social mobility may be constructed. We propose a family of three state-by-state and aggregate (scalar) predictability measures. The first set of measures is based on the transition matrix. The second uses a sampling approach and permits statistical testing of the hypothesis of perfect mobility, providing a new justification for the use of the chi-squared statistic. The third satisfies the demanding criterion of "period consistency." An empirical example demonstrates the usefulness of the new measures to complement existing ones in the literature. Copyright 2001 by The London School of Economics and Political Science