The idea that viewer engagement with a particular programme affects the impact of ads within it is “a myth”, Ace Metrix said.

The firm, founded in 2007, uses a “creative engagement” score, which measures the effectiveness of ads regardless of where they appear.

Its study, based on a database of more than six million responses to 12,000 ads and a survey of viewer behaviour, found no statistically significant difference between the scores given to ads by people who were the most and least engaged with the programmes where the ads appeared.

It quantified engagement by looking at how regularly people viewed different shows, and found this to be closely correlated with other signs of engagement, such as recording a show on a DVR or talking about it with friends.

Peter Daboll and Michael Curran, CEO and director of advertising analytics at Ace Metrix, said the notion that media should be bought on the basis of viewer engagement rather than just audience size and composition, “will fade – not because it isn’t an interesting idea, but because the empirical data disproves it as a myth”.