Guide | Data Comparisons

What is a base and how do you choose one?

Gathering audience data usually requires a certain amount of effort. To benefit from that effort, audience data has to be useful. To be useful, data has to be interpreted or given meaning, so one way of giving data meaning is to place it in context by comparing it to another set of data. Data comparison is common in many industries and sectors. A familiar example can be seen in the pharmaceutical sector and their use of the placebo – one set of people trial a new drug, another set of people are given a placebo and these two sets of people are compared.

The comparison of audience to population is a fundamental one that can be used to interpret audience data. This helps to identify particular groups who are more inclined to engage as audiences, as well as those who are the least disposed to do so (these are seen in the data as those who are over-represented in an audience profile compared with the market population (i.e. more likely to attend), and those who are under-represented (i.e. less likely to engage with an organisation, venue or event).

Defining a population

To use population data, it’s helpful to identify a specific population by defining the area in which that population lives. There are a handful of ways to easily define a geography - by country, local authority area, drive-time from a venue or site of an event, or by plotting the audience’s geographical reach (or, “footprint”) to create a bespoke catchment area.

Each of these methods has its own particular advantages and weaknesses, but their common aim is to compare the audience profile to that of the population living within the most relevant particular catchment area, however it has been defined.

For example:

  • When drive time or distance is used – the proportion of the audience that is drawn from within, say, a 30 minute drive-time of a venue or event can be understood. This not only helps to demonstrate a venue or event’s geographical “reach”, but also enables comparison with the profile of the overall population that lives within the same defined area.
  • Alternatively postcodes from audience data might be mapped, so that a catchment area in which a high proportion of the audience live (a “core” audience) may be defined. In this example, postal sectors are ranked according to the number of audience members that live in them, and then an area is defined by plotting the top-ranking postal sectors that, when combined, contain a certain percentage of the total audience (this can often, typically be 75% of the total audience). In this way the audience profile can be compared very specifically against the total population of the geographical area which most particularly reflects the current reach of the venue or event.

What is a base?

Whichever way audiences are compared to a population, the term commonly used to describe the population is ‘base’. Comparing audiences with a different base has a number of predictable impacts on the interpretative power of that comparison.

A comparison of audiences to a national base – the population of England, for example. This comparison is a broad-brush one that might be best used to compare venues doing similar work in different parts of the country. Such a comparison will hide significant local differences in population. If the local population varies from national averages, then comparison of audiences to a national base may well make an audience appear more distinctive than it really is.

A comparison of audiences to a local base – the population within a local district authority area, for example. This comparison is one that might be best used to compare venues in different parts of a county. Such a comparison will hide significant local differences in population. If the local population varies from county averages, then comparison of audiences to a local authority base will make an audience appear more distinctive than it really is. However, district authorities may well value this sort of analysis, as it helps them to see which sections of their resident population are engaging with, or being served by, the particular venues or events.

A comparison of audiences to a catchment – the area in which 75% of audiences live, for example. This comparison is one that might be best used to understand engagement at the venue level. Such a comparison will align with local differences in population. This is a powerful comparison at venue level, showing the audience strengths and weaknesses based on the current offer most effectively, but is less easy to use when looking at understanding engagement in the cultural offer of a particular place, county or nation.

Things to consider


Using data of course is more challenging of course than simply gathering or looking at it. To get value from your data, it then needs to be combined with judgement. That judgement will often be based upon a set of assumptions. Strong assumptions are based upon evidence and are framed in ways that future data collection can validate. For example, a one-day festival expects to gain audiences from within a 15 minute drive-time of their festival site and expects family groups to make up 65% of audiences – these expectations are reflected in the programme, communications and an early evening finish time. An audience survey however, shows that the drive-time is slightly larger and that family groups actually make up 85% of the audience. Based on this knowledge the event communications could be developed to cover a wider geography to maximise future awareness.
Articulating judgements and assumptions made using these base variables will therefore help you to be clearer about what you think is most important to understand when it’s time to think about developing your audiences.