Higher psychological well-being among married as opposed to unmarried persons may be due to social selection into marriage, or to marriage effects (social causation). From the selection hypothesis it follows that well-being at one time point be positively related to the subsequent probability of marrying. Using transition rate methods (Cox regression) on a sample of 9,000 unmarried persons, strong and significant relationships are found. The predictive power of the well-being measures remains stable throughout the 2- to 4-year period of observation. It is concluded that selection may play an important part in producing the oft-observed association between marital status and well-being.
Mastekaasa, A. (1992). Marriage and psychological well-being: Some evidence on selection into marriage. Journal of Marriage and the Family, 901-911.