The Marriage Equation
A practical theory for predicting divorce and a scientifically-based marital therapy
James D. Murray
Emeritus Professor of Mathematical Biology
University of Oxford
&
Emeritus Professor of Applied Mathematics
University of Washington
The rise in divorce rates in developed countries is a
widespread but poorly understood phenomenon. Previous attempts at
predicting marriage dissolution tend to be based on mismatches in the
couple's personality or areas of agreement; these have not been too
successful. I shall describe a simple, but surprisingly predictive,
mathematical model, based on only a few parameters describing specific
marital interaction patterns. The mathematical model characterizes
differences between different types of stable couples whose marriages
are likely to last from two types of unstable couples. I shall show how
a couple’s interaction data are collected, how their parameters
are determined and what they predict for a couple’s marital
future. In a 12-year longitudinal study on a large number of marriages
the model predicted divorce with an accuracy of 94%. The work has
helped us design new scientifically-based intervention strategies for
troubled marriages which are proving encouragingly successful in
clinical practice.