The Process of Entry into First Marriage

A mathematical model is developed for the process of entry into first marriage. The members of a cohort are seen as subject to two types of forces. One is the increase in social pressure to get married as the percentage of the cohort already married increases. The other is the declining marriageability of members of the cohort as they grow older. With some additional assumptions, this gives rise to a non-homogenous diffusion model. The model is illustrated with U.S. Census data, and factors contributing to deviation between observed and predicted distributions are discussed. Other applications of the diffusion model are suggested.