Natsal over time

The Natsal team reviews the wording of questions carefully for each round of the survey. There is a delicate trade-off between updating any wording to ‘move with the times’ and keeping the questions exactly the same so the time can measure change over time in behaviours and attitudes.  

In order to assess change over time, and be confident that this reflects real change, questions need to be worded in the exact same way in each survey, so that the resulting data can accurately be compared ‘like for like’. Other steps to help achieve this include presenting response options in the same order and asking the question in the same part of the interview, in the interviewer-administered part rather than in the self-completion sections (or vice versa). 

However it is important that questions are meaningful to participants and this does require updating phrases. Natsal endeavors to make sure that the wording used is the most relevant for the times. For example, Natsal-1 and Natsal-2 asked participants ‘Have you ever attended a sexually transmitted disease (STD) or special venereal disease (VD) clinic?’ but for Natsal-3 the question instead referred to ‘sexual health clinics’ and in Natsal-4 ‘service health services’, which is the more common name for these services nowadays. 

Natsal surveys are carried out around every 10 years to help us understand how sexual behaviours and attitudes in Britain may be changing over time. Some of the changes we see are likely to reflect real shifts in how people think and act when it comes to sex and relationships. However, it’s also important to remember that results can be influenced by other factors such as the methods used to conduct the survey and reporting bias (e.g. the willingness of participants to report certain behaviours or their ability to recall information accurately).   

The Natsal team has explored the differences between surveys to better understand what the changes mean and how they reflect real shifts in sexual attitudes and behaviours in Great Britain. Between Nastal-1 and Nastal-2, we saw an increase in willingness to report sexual behaviours. This may have been due to changing views about sex and relationships or the way data was collected; moving from pen and paper interviews to computer-based interviews. This shift in interviewing may have made people feel more reassured of confidentiality in their responses, resulting in more accurate reporting and increased participation, particularly among those with sensitive sexual experiences.   

Between Natsal-2 and 3, the methods stayed more consistent, so changes are more likely to reflect real shifts in behaviour. For Natsal-4, new methods like telephone and online surveys were added, and recruitment methods also changed, making it more difficult to determine the extent any observed changes between Natsal-3 and 4 reflect true change.    

The age range of those who have taken part in Natsal has changed with each survey round. For Natsal-1, those aged 16-59 were eligible, but this narrowed to 16-44 years for Natsal-2 and widened to 16-74 years for Natsal-3. Those aged 16-59 were eligible to take part in Natsal-4.  

The Natsal team takes account of many factors when deciding age eligibility, including research priorities at each time point, availability of alternative sources of data and information, and the level of available funding. For example, a key objective for Natsal-3 was to explore sexual behaviour over the life course, and this resulted in an extended eligible age range (16-74 years). For Natsal-4, it was decided to narrow the age range again due to the availability of alternative sources of data on sex and relationships of older adults in Britain.  

To ensure that Natsal stays relevant and can explore contemporary issues and key policy and practice concerns, the questionnaire is reviewed and revised at each round. New topics explored by Natsal-4 include: 

• the use of porn and its impact on individuals’ sex lives,  

• experience of sexting (using digital technology to send or receive images or videos that show the sender’s genitals, buttocks or breasts, or shows a person engaging in sexual activity), 

• seeking partners online (e.g. using social media apps, dating websites, chatrooms) and resulting sexual partnerships, and 

• sexual wellbeing, including questions about comfort with own sexual identity, upset about sexual past, and sexual pleasure. 

The first three Natsal surveys didn’t ask participants about their gender or sex (as assigned at birth); rather the interviewer concluded and recorded whether the participant was female or male based on their outward appearance (e.g. their clothing) and their name.  

These observations were then used to make assumptions about the participant’s sexual anatomy for the rest of the interview. However, this approach is limiting and results in some misclassification, which needs to be considered when interpreting data from earlier rounds of Natsal. 

In contrast, Natsal-4 asked both about participants’ gender and their sex assigned at birth, because a person’s assigned sex doesn’t always align with their gender. It further asked people whose gender is different to their assigned sex at birth additional questions (e.g. have you gone through any part of the process to change from the sex you were described as at birth to the gender you identify with?). It is important for Natsal to ask these questions to make sure participants are asked the right questions throughout the survey.  

Sexual violence refers to sexual activity that happened without consent. By consent we mean fully agreeing with full capacity. This means that a person has to be able to agree to sexual activity with full understanding of what they are agreeing to, and they must be under no pressure to say ‘yes’. Natsal-3 asked about non-consensual sex for the first time. 

In Natsal-4, additional questions were added to explore sexual violence. In the self-completion section of the interviewer administered survey, participants were asked “since the age of 16, has anyone ever made you have sex when you did not want to or when you were unable to refuse?” Further information such as frequency, relationship to perpetrator(s) and whether they told anyone was also collected. Coercion to take part in any other sexual activity since individual had turned 16, and coercion to take part in sex or any other sexual activity before the age of 16 was also asked about.