"The reason we invest more in Google is that search is more powerful in my view than social," Sorrell told the Creativity+Science event. "With search, you can see the results." However, he added that social was useful at building brands over the long term.
H+K parent firm WPP will, Sorrell estimates, invest around $5.7bn on search marketing with Google and other search engines this year, up from $4bn last year, compared with $1.7bn for Facebook, up from $1bn.
He also pointed out that while social media had changed the PR industry, data should still be seen as "the backbone" and key to "measuring the outcome" of PR.
Discussing the changing role PR agencies play today, Sorrell said it was still up for discussion how integrated agencies needed to be.
And he said that 30 years ago, an advertising and marketing presentation would start with a planner - and "if you were lucky" you might get to a media planner, and then a PR planner. "Today you start with the data and are more likely to go to the media planner," he said, adding that he thought that "the medium has become more important than the message" nowadays.
Sorrell also had time to share a few more thoughts on the upcoming US election.
"I still think Hillary [Clinton] will win though Monday night will be crucial," Sorrell said, while admitting that his 'remain' prediction in the EU vote had been wrong. When it came to brand Trump, he said: "Whatever you feel about what he says, he has tapped a nerve, which means something."