Surveys: why do we… ask so many personal questions?

When we do surveys, we often collect a large amount of information from respondents that they may feel is personal to them and is not relevant to the topic of the survey.

This data may include, for example:

  • Postcode
  • Gender
  • Age
  • Ethnicity
  • Disability
  • Occupation
  • Education

We usually collect this data in the form of a question requiring an answer specific to the respondent such as your actual age or self-defined gender. Alternatively, we might collect what we call ‘grouped’ data such as an age range (e.g. 21 – 30 yrs; 61 – 70 yrs of age) or a set of answers each of which groups many possible answers into a small number of options, such as with ethnicity.

Example of an Ethnicity question from an online survey

On the face of it, inclusion of these types of question may seem abstract or even intrusive, but there are very good reasons why we do this.  The two most important reasons are:

First, it allows us to check and see if our survey respondents are similar to, and therefore representative of, the wider population.  When we do a survey we are only obtaining a small sample of the total population and it is important for us to know whether that small group is a statistically valid representation of the larger population.  If we can show it is statistically similar then the quality of our results will be higher and we can use the survey data as a valid representation of the larger population.  Our analysis will also carry more weight with policy makers and others with an interest in the results. 

Second, it enables data which are collected through the survey to be compared to other data sets, which may have been done in previous years (in which case we can look at trends over time) or in different parts of the country.  Having a good understanding of the main characteristics of people in our survey sample is important when undertaking comparative work.  Examples of key data sets we utilise for comparative purposes include: UK National Census data which occurs every 10 years, data available from other Government Agencies such as the Office for National Statistics (ONS), or the Higher Education Statistics Agency (HESA), and the National Audit Office. 

Other reasons

There are also other reasons for collecting this information, which includes: it allows us to compare and contrast between different sectors of society, such as comparing male with female responses, old people compared to young, or responses from people who live in one area with those living in a different area. This gives the potential to identify factors which may be influencing the results, and to help explain the reason for differences in responses to questions that may be present.


When you give us your postcode, you don’t need to worry. Postcodes only identify your location to maybe within a hundred metres or so and won’t reveal a specific building in all but the most remote locations, and we are only allowed to use it for the reason in the survey – we won’t be sending you any marketing material. Postcodes let us do some clever stuff though. As well as showing us the location of respondents, when combined with other questions, we can map how far people travel or are prepared to travel, map routes and consider the impact this may have on their activity, or map their contacts into a geographic representation of their social network. Postcodes also allows us to identify whether the location is classified as ‘rural’ or ‘urban’, or in which district, county or region a location is. This is very useful to allow us to analyse the data at much larger geographic areas, to again investigate whether there are regional trends, and also to allow us to check whether our sample is evenly distributed at a geographic level.

Data is kept confidential

Lastly, just to note that you can give all this data to us without concern. All the data we collect is managed under the requirements of the Data Protection Act (2018) and the General Data Protection Regulations (GDPR). In short, what this means is that we have to look after your data and keep it secure, not give it to another organisation, use it only for the purposes that we have said we will use it for, and give you the opportunity to ask for it to be deleted.


So whilst completing this section of a survey can be a tiresome exercise, please do persist as it makes all of the other responses, and the time you take to give them, much more worthwhile and valuable ….[and allows us to ensure that the work that we do is more reliable/robust when scrutinised ]