Currently, when a viewer goes into an interactive application, Barb registers the viewer as continuing to watch the channel irrespective of if they are voting or sampling an ad.
There has been concern that with interactive voting, viewers are in fact missing the ad break entirely, despite Barb recording them as viewing it.
The matter is becoming of increasing concern to agencies given the increase in digital viewing - the number of digital households has already hit the 50 per cent mark.
Agencies are claiming that TV shows with interactive voting elements, such as Big Brother, are starting to distort viewing patterns.
Andy Zonfrillo, the broadcast director at MindShare, said: "If broadcasters start asking viewers to interact with programming rather than watching the ads, then this is an issue."
Chris Williams, the UK TV buying director at Starcom Motive, said: "The fact that Barb currently doesn't measure viewers interacting with ads is not a big issue but the inexorable growth of digital and increasing levels of interactivity suggests it needs to be addressed soon."