Measuring pre-broadcast 21 May 2019 It is clear that UK viewers love having access to programmes on-demand via the BVOD service apps on their devices. Primarily this is to catch up on shows they have missed in the linear schedule; but increasingly, viewers can see future episodes in a series before their linear transmission. Series stacking is when an entire series is made available through a BVOD service, usually on the day the first episode is broadcast. Several UK broadcasters have made programming available this way and, with BARB measurement, this provides opportunities to observe how viewers behave in an even more on-demand world. Research by ITV and Channel 4 in 2018 showed that 11% of people ‘have nothing in mind’ when they go to BVOD services, a figure that’s more than doubled in two years. Viewers are using these services not just to catch up, but to discover new things to watch. Crucial to BARB’s ability to identify this pre-transmission viewing is broadcaster collaboration by providing audio files that allow BARB to recognise the programme viewed. By December 2018, BARB was tracking over 2,500 non-linear programme audio assets, almost a ten-fold increase in under two years. Sky Atlantic’s Save Me illustrates how viewers behave when a series box set is available on-demand. The data are enhanced by BARB’s ability to distinguish between post-transmission timeshifted and on-demand viewing on TV sets in Sky homes. This chart shows that viewing on-demand makes up 80% of the total to the series. 69% of total viewing to episodes 2-6 was before the live transmission – a proportion that rises steadily, from 53% to episode 2 to 83% to the final episode. Separate analysis points to some box-set bingeing, with 128,000 people devouring all six episodes the day after episode 1’s broadcast, and a further 623,000 polishing off the whole series in the days before episode 2 went out. So-called traditional viewing behaviours – of live viewing (almost invisible in these data) and catch-up via timeshift – account for less than 20% of the total. On the BBC, we have another example of how box-setting is transforming viewer behaviour. Killing Eve premiered on BBC1 on September 15th 2018, with all episodes available on BBC iPlayer simultaneously. A snapshot of episode 6 breaks down viewing into pre-broadcast, live and post-broadcast; as well as identifying which devices were used for each. The inner part of the pie shows more than half of the audience (52%) viewing pre-transmission; almost a fifth watching live, and 29% viewing post-broadcast. Pre-transmission viewing saw the highest use of non-TV devices, with an average audience of 812,000 on a PC, tablet or smartphone; the vast majority (83%) on the bigger two screens and only 136,000 on smartphones. Live viewing was almost entirely on a TV set, with only 12,000 watching live on a PC, tablet or smartphone. Devices came back into the picture a little more for catching up, although only accounting for around 8% of viewing there. The dominance of TV set viewing – whether pre (84% of total), live (99%) or catch-up (92%) – is a reminder of how much viewers prefer the big screen. As broadcasters continue to experiment with box-setting series, it seems certain that we’ll see viewing behaviours continue to evolve in the emerging television ecosystem.