It had originally been expected to launch last month (March) and has been working with Kantar Media on the cross-device content evaluation and methodology.

Barb said it had taken longer than expected to produce the multiple-screen viewing figures to the standard expected by the industry.

Once established, Project Dovetail will allow Barb customers to have access to the number of people that are watching programmes across four screens: TV sets, tablets, PCs and smartphones.

It has been beta-testing the new reporting since 2015, delivering data  on the number of tablet, PC and smartphone devices being used to watch programmes, both on demand and live streaming.

Barb is collecting data from software meters on tablets and PCs in its UK panel homes as well as census-level streaming data from viewing apps enabled by their owners to deliver duration-based information to Kantar Media.

Barb said it had also been asked if its data collection and reporting techniques could be applied to online video services, such as Facebook and YouTube.

This content is more likely to be short-form and user-generated, and isn’t covered by broadcast regulations that ensure brand safe environments.

As a result, Barb commissioned a cross industry consultation, carrying out 35 interviews with businesses in different parts of the industry including advertisers, agencies, broadcasters and social media platforms.

Barb said two points emerged: the joint industry currency principles underpinning Barb should not be weakened or compromised; adding channels or platforms should not impact on the integrity of Barb’s data collection and reporting methodology.

The consultation clarified that advertisers and agencies expect any cross-platform audience currency to follow established TV conventions for duration, viewability and verification and that brand safety was paramount.

Barb added that the next priority for Project Dovetail, after the launch of people-based cross-platform programme viewing figures, is to deliver an equivalent measure for viewing online TV commercials.