Natsal-4

We undertook a Scoping Review to consider the most appropriate methodological approach for Natsal-4. This review assessed methods used to date by other major UK population surveys and by population surveys of sexual health internationally. The review distinguished between sampling methods and recruitment/data collection mode (e.g. face-to-face, web, telephone) as each have distinct implications for data quality and resource.

The findings have been published as a scoping review and also published as an Editorial in the journal, Sexually Transmitted Infections.

The fourth Natsal survey will interview around 10,000 people aged 16-59 years. Survey answers will be combined with information from biological samples (e.g. urine to test for sexually transmitted infections) and routinely collected data (e.g. health records). We will oversample (‘boost’) young people to allow more detailed statistical analyses of this group.

The age range covered by Natsal has varied with each survey round. Although we wanted to include people over 59 years in Natsal-4, there were limited resources available and this was one of the difficult decisions we had to make. Natsal-3, which included people aged 16-74 years, focused on how people’s experiences vary throughout their lives.  Natsal-4 will focus more on young people, including oversampling 16-35 year olds so that we can better understand variation within this age group. This is because young people experience the greatest social and sexual changes and are more likely to experience adverse sexual health outcomes than other groups.

We will invite men and women to provide samples to test for sexually transmitted infections (STIs) (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, and for women only Human Papillomavirus (HPV)). These will be urine samples for men, and for women we will explore the feasibility of self-collected vulvo-vaginal swabs because these allow more accurate testing. We will assess the feasibility of returning clinically relevant results to participants using an online NHS results service. The biological samples will be stored in a biobank so that they can be used for future research. For example, the samples could be tested for the microbiota, which are the groups of microorganisms which inhabit our bodies: some are beneficial, but others may cause illness.

All Natsal-4 participants will be invited to consent to link their survey and biological data to their health records and other routinely-collected data. Linking these records creates opportunities to expand the range of data we have to answer complex research questions in ways that have not previously been possible.

We received 294 responses (online and via email); 30 from organisations and 264 from individuals including members of the public, researchers, clinicians, policy makers, educators, and those representing voluntary or community groups. 

In addition to commenting on topics that consultees thought should be added or removed, consultees were asked to rank the importance of topics which have been included in the previous Natsal surveys, and new topics planned for Natsal-4. The five highest ranking topics were: ‘Experience of sex against your will’, ‘Gender identity’, ‘Sexual attraction, experience and identity’, and ‘Use of sexual health services and testing’ .

Consultees proposed many new topics and specific questions they thought to be relevant for Natsal-4, and there were relatively few suggestions for topics to remove from the existing questionnaire.

The consultation responses fed into a series of prioritisation exercises (undertaken August-September 2019) to determine which questions would be taken forward as part of the questionnaire for the Natsal-4 pilot study. This was necessary due to restrictions on the overall feasible questionnaire length (under 1 hour) against the large number of potential new topics and questions and the need to retain many questions from previous surveys.

Consultees also proposed improvements to existing questions, which fed into a wider questionnaire design review. Decisions about which changes to make balanced the need to make improvements to the existing questionnaire (some sections were initially developed in the late 1980s) with the need to keep core question wording the same to enable examination of change over time.

For each section of the questionnaire, a summarised version of consultees’ comments and the corresponding decisions is provided in section 6.3 of our full report.