Sociology Plus
Benini Coefficient Definition
The Benini coefficient is a statistical measure, derived from the chi-square statistic, used to summarise patterns of movement within a social mobility table. It offers a broad description of how much movement occurs between origin and destination classes across generations, while adjusting for the fact that the relative sizes of those classes change over time.
What It Measures
The coefficient captures both immobility and mobility — that is, the association or dissociation between where people start and where they end up — relative to the limits set by the shifting size of each class. Its values run from +1, indicating more mobility than would be expected from the changing size of the classes alone, to −1, indicating less mobility than expected. A value near zero points to an essentially random pattern of movement between generations.
Place Among Mobility Measures
The Benini statistic belongs to a family of measures designed to separate mobility caused by changes in the occupational structure from mobility due to other factors. Related tools include the index of association, disparity ratios, and odds ratios. All of these share a common limitation compared with the newer technique of log-linear modelling: unlike log-linear methods, they do not allow the analyst to test competing models of mobility against one another and compare how well each fits the data.