For a long time, television audiences were defined by a single means of viewing and so were relatively easily measured. Viewing took place in the home and only via the box in the corner of the living room or bedroom. So household demographics and viewing patterns could be measured and extrapolated from relatively small but representative panels of the viewing population. With a comparatively limited range of channels and the majority of viewing being simultaneous at the time of transmission the task was relatively simple. The explosion in TV content and the ability to view it on different devices at different times and in almost any location has made measuring and evaluating that audience much more complicated.
At its simplest the audience can be defined as the number and nature of those who have viewed a particular piece of content, usually a programme of some type or a commercial within that content. However, the increasingly varied ways in which consumers access and view programming means that our understanding of the audience figures needs to take account of any or all of the following:
- For broadcast TV – (also referred to as 'linear'), how much of the recorded viewing took place on a day or at a time other than that of the original transmission? (This is often referred to as 'time-shift' viewing, usually of recordings from linear or via digital catch up services either via a set-top box or the internet.)
- For 'on-demand' services such as Netflix, Amazon, or other pay-per-view services via the net or set-top box, how does the audience accumulate over time and how is that reflected in the audience figure?
- The increasing trend towards viewing two or more pieces of content on different devices at the same time ('second-screening') may also require some measure of how much time or attention was spent on the content being measured.