Study members were first asked for details of their marriages in 1965. This information was updated in 1966,1968 and 1971.
In 1972 study members were asked to confirm their marriage details and were also asked about their spouse's and their parents' marital history; this information was updated in 1977. In 1982 a full marital history was recorded from their first marriage to the present day, this was updated in 1989 (or collected from new if the study member was not interviewed in 1982), and updated again in 1999.
In 2006-10 and 2014-16, study members were asked if, since the previous data collection, they had married, remarried, separated, divorced or had been widowed.
At each wave, study members were asked to the number of marriages and how each marriage ended. The year of the start and end (if relevant) of each marriage has also been recorded.
A set of derived variables was created for: