National Survey of Sexual Attitudes and Lifestyles 1990 and 2000
The National Survey of Sexual Attitudes and Lifestyles, or Natsal as it became known, is the largest study of sexual behaviour since the pioneering studies of Alfred Kinsey in the US in 1940s and 50s. Natsal was originally set up in response to an urgent need for information about sexual practices in the context of the HIV and AIDS epidemic. In the mid 1980s, little was known about the sexual behaviour of people in Britain. Relatively small scale surveys and qualitative studies of the behaviour of particular groups had been carried out, but there were no national prevalence data on numbers of sexual partners, frequency of different sexual practices, and homosexual experience. The first Natsal, carried out in 1990, had the quite specific aim of providing the data needed to assess the likely spread and scale of HIV infection in Britain, and to inform strategies to prevent transmission.
In the event, the data set created by Natsal 1990 was used far more widely than had been anticipated, in sexual health epidemiology, policy and practice. Towards the end of the 1990s, the data were becoming outdated and repeat measures were needed, to look at changes in behaviour over time and to take account of current information needs in the field of sexual health. As a result a second Natsal was carried out in 2000, the main objectives of which were to:
- provide a detailed understanding of patterns of sexual behaviour in Britain;
- provide data for HIV/AIDS projections in Britain;
- assess whether there have been changes in behaviour since Natsal 1990; and
- measure the prevalence of chlamydia trachomatis infection, via urine samples.
To ensure comparability of the data, Natsal 2000 needed to be modelled closely on the 1990 survey. Like Natsal 1990, Natsal 2000 was a cross-sectional study using a multi-stage stratified random sample of men and women living in private households in Britain. The 2000 survey used face-to-face interviews to ask questions on general health, family background, learning about sex, first sexual experience, contraception, attitudes, and household classification. A self-completion component was used to ask questions of a more personal and sensitive nature, for example on: sexual attraction, experience and orientation; sexual partnerships and practices; frequency of sex; and topics relating to sexual health outcomes, such as sexually transmitted diseases, HIV/AIDS testing and sexual problems.
At the same time, methodological developments in survey research in the period between the two surveys had led to improvements in data collection. In particular, studies had shown the potential of computer assisted interviewing methods to improve response rates and data quality, in particular the disclosure of sensitive behaviours. In Natsal 2000, Computer Assisted Personal Interview (CAPI) and Computer Assisted Self-interview (CASI) techniques replaced the pencil and paper methods used in the earlier survey. Other changes were made to the 2000 survey:
- Natsal 2000 sampled a younger age group (aged 16-44) than did Natsal 1990 (aged 16-59), in order to focus survey resources on a group at greater risk;
- residents in the Greater London area were purposively over-sampled;
- a boost sample of people from four ethnic minority groups - Black Caribbean, Black African, Indian and Pakistani - was included;
- new question modules were introduced, for example on partnership formation, sexual mixing abroad, sources of contraception and advice, experience of sexually transmitted infections, and sexual dysfunction;
- a urine specimen was collected from consenting respondents, and tested for chlamydia trachomatis .
Importantly, the wording of repeated questions remained unchanged.
Financial support for Natsal has been supplied by several funding agencies. The initial feasibility study (1987-1989) was jointly funded by the Economic and Social Research Council and the Health Education Authority; the Wellcome Trust funded the main stage of Natsal 1990; and Natsal 2000 was funded by the Medical Research Council.
Natsal 1990 and 2000 data are archived at the ESRC Data Archive at the University of Essex.
The Natsal 2010 is currently being developed and fieldwork is due to start in September 2010. Click here for more details.