What is Natsal?

Natsal has collected data through four surveys, conducted during the following periods: 

• Natsal-1: 1990-1991 
• Natsal-2: 1999-2001 
• Natsal-3: 2010-2012 
• Natsal-4: 2022-2024 

Data collection for Natsal-4 was originally due to begin in 2020, but was delayed because of the COVID-19 pandemic. When fieldwork began in 2022, the Natsal team offered different ways of taking part to make participation easier and safer, such as by offering interviews over the telephone or online. A shorter online questionnaire was also available for people who did not wish to take part in the full interview. 

Initially, Natsal-4 used the same recruitment approach as previous Natsal surveys. Households were randomly selected from a list of all postcodes in Britain, and one eligible person in each household was invited to take part. As people were selected at random to take part, this approach gives everyone in the population a known chance to be selected. It is seen as one of the best ways of getting a sample that is truly representative of the whole population.  

Natsal-4 also used new approaches to interview as many people as possible. This included inviting people from an existing research panel made up of individuals who had previously been recruited using random sampling for a different survey. Information from participants recruited through these first two methods is used by the Natsal team to estimate how common different sexual experiences and behaviours are in Britain. The 'Sex Stat for Britain’ tool at the end of this resource uses this data to allow you to explore findings from Natsal-4 to see how outcomes vary between different groups in Britain. 

Natsal-4 also recruited some participants through an online panel where unlike the previous samples, these people were not chosen at random. Data from these participants are not used to estimate how common behaviour, experiences or attitudes. Instead they are used to help the Natsal team explore the relationship between outcomes are related to different characteristics and circumstances while accounting for differences between participants.

The Natsal team made sure that participants were from a variety of backgrounds, including various age groups, genders, and geographic locations, so that the mix of participants still closely reflected the wider population of Britain.  

More information about the Natsal study methods can be found here.

Natsal-4 used a range of interview methods (face-to-face, telephone, or online).  The full questionnaire was offered either face-to-face or over the phone and took about an hour to complete. There was also a shorter online version, which people could complete on their own in around 20 minutes. 

Using a range of methods meant Natsal could increase the number of people who took part, and it made it accessible to people who wouldn’t take part in a face-to-face survey.  

However, the way that data is collected might influence how people respond to questions. This creates challenges when combining data from different collection methods. When answers differ between groups, it can be difficult to know whether those differences reflect people’s actual experiences, behaviours and attitudes or the way the survey was completed. The Natsal team is careful to take this into account when interpreting the findings.  

Of all those who were invited to participate in Natsal-4, around 1 in 4 people agreed to be interviewed – this is similar to other major national surveys. Across all the ways of recruiting participants, a total of 19,000 people took part. 

While it is becoming more challenging to recruit survey participants, especially since the disruption of the COVID-19 pandemic, reflections and learnings from the Natsal-4 fieldwork will provide valuable insights to strengthen the capacity for future research to engage the population, both in the UK and internationally.  

Natsal covers a wide range of deeply personal topics, such as sex, relationships, sexual health and experiences such as sexual violence. While some questions may not seem sensitive to everyone, they can be upsetting to some.  

The Natsal team designed the survey in a way that puts participants’ wellbeing first. For example, in the section about sexual violence, an emergency exit option was included so participants could choose to skip questions or leave that part of the survey. Throughout the survey, participants were free to skip any questions they did not want to answer. At the end of the survey, links to relevant services were provided for anyone needing further support. 

To acknowledge their time and valuable contributions, people who took part in Natsal-4 were offered gift vouchers or points that could be exchanged for prizes as a token of appreciation.