The GHS has collected details on current marital status since it started in 1971. Over time the questions have been extended to include the de facto marital status - that is including cohabitation - reflecting the way society has changed, making the GHS a key source of information on these topics. Questions on marital history for both men and women were introduced in 1979. In the same year, questions on pre-marital cohabitation before the current or most recent marriage were introduced for women aged 18 to 49. These pre-marital cohabitation questions were extended in 1986 to include questions on pre-marital cohabitation before every marriage past and present and, since then, have been asked of both men and women aged 16-59. In 1998, a further question was added concerning the number of past cohabitations which did not end in marriage.

As part of the extensive redevelopment work for the GHS in 1999, Social Survey Division carried out a programme of cognitive testing based on a series of questions developed in ONS to explore the feasibility of extending the questions on cohabiting unions to collect information on the duration of such relationships. The outcome of this work was reported in the Survey Methodology Bulletin. New questions on duration of past cohabitations which did not end in marriage were included in the 2000/1 GHS. These included the dates of the start and end of cohabitations and what people perceived to be the end of each such cohabitation (the end of the relationship, the end of sharing accommodation or both).

Information about the marital status of all adults aged 16 or over in the household is first collected from the person answering the household questionnaire (usually the household reference person or their partner). Each household member aged 16 to 59 is asked detailed questions about their marriage and cohabitation history later in the interview. Where interviewers judge that lack of privacy may affect reporting, they can offer respondents a self-completion questionnaire to fill in. In 2000, 5% of respondents chose this option.

With the extension of the questions about cohabiting unions which did not end in marriage, this chapter focuses on cohabitation but starts with a brief overview of current marital status.