Project Dovetail


The UK television industry has changed beyond recognition since BARB’s launch in 1981. Since then, we have continuously developed our audience currency in response to fragmenting behaviour patterns. There has been a proliferation of platforms, channels and catch-up services, and in recent years more people have started to watch television through the internet.

BARB’s objective continues to be based on our customers’ requirement for a comprehensive and trusted measurement of viewing to programme and commercial content, regardless of delivery platform. To this end, Project Dovetail was established to deliver total reach of programme and commercial audiences across multiple screens.

Our method for achieving this relies on two high-quality data sets:

  • BARB’s panel of 5,300 homes delivers representative viewing information that includes programme and campaign reach, demographic viewing profiles and measurement of viewers per screen.
  • BARB collects device-based data whenever anyone in the UK watches a BVOD service on a tablet, PC or smartphone. These data provide a census-level measure of what’s been watched and for how long.

These two sources are combined using a process called Dovetail Fusion. This delivers multiple-screen viewing figures that are being released in four stages:

  1. Collecting and reporting device-based census data – in 2015, we launched the TV player report – now the BVOD services report – which includes viewing time via all BARB-reported BVOD services on PCs, tablets and smartphones.
  2. Programme average audiences – since August 27th 2018, we have reported multiple-screen programme audience figures for all individuals across four screens: TV sets, tablets, PCs and smartphones. The weekly top programmes on four screens can be found in our new dashboard. BARB clients can also analyse demographic profiles across three screens, TV sets, tablets and PCs; these data are available through registered data-processing bureaux.
  3. Reach and time spent viewing – in January 2020, we began to report unduplicated reach and time spent viewing across three screens: TV sets, tablets and PCs. This total three-screen viewing is reported alongside consolidated seven-day TV set viewing, which has been our definition of total TV. Smartphones will be included when we deploy our router meter solution for measuring our panel members’ viewing on these devices. BARB customers and data-processing bureaux can access daily respondent-level data within the new cross-platform panel viewing file (PVX), allowing more extensive analysis.
  4. BVOD campaign performance – the development of tags for BVOD commercials is in process; this will be followed by a methodology review, development and testing, user acceptance testing and stakeholder review. The expected launch date is in the first half of 2021.

To find out more about how we produce multiple-screen viewing figures or for the answers to commonly-asked questions about multiple-screen viewing, such as why smartphone viewing is only available in programme average audiences, please visit our multiple-screen viewing FAQs. BARB customers can also access our new training module.

Project Dovetail meets the first of our strategic priorities: to address the rise of online delivery of programmes and commercials with multiple-screen viewing figures. Our second strategic priority is reporting dynamic ad insertion; you can read more about this in this BARB Explained. Our third priority is to address the growth in unidentified viewing on TV sets, which includes viewing to SVOD services like Netflix and Amazon Prime Video. You can read more about this in our future development FAQs.