The firm’s published audience figures currently only include those watching live and recorded programmes on their TV, ignoring the estimated 2% of television viewing via websites and tablet apps, such as iPlayer and 4oD.
However a new system developed by Kantar Media will now measure how many laptop, iPad or Android tablet users are also watching shows.
This could potentially boost published audience numbers for BT Sport, which offers free app-based access to its three channels to all broadband users, and local TV stations such as London Live which offer website access to their channel.
It could also see audited viewing figures published for online exclusives such as the BBC’s Doctor Who Extra which takes audiences behind the scenes of the hit Sci-Fi show.
BARB says around half of the homes making up its audience panel already have tablets which could be measured.
Chief Executive, Justin Sampson, said: “The ability to track how our panel members watch television on their tablets is a great step forward and another staging post for the delivery of Project Dovetail.
“It is also the catalyst for us to build a new panel of homes that have broadband connections but no TV sets.
“Additionally, we now plan to accelerate deployment in our panel of the software meters that track viewing on laptop, desktop and tablet computers.”