Can Machines Beat the Pollsters?

Can learning machines that gauge public opinion using Tweets or smartphone adverts perform better than traditional polling? We talk to Rob Lancashire of Essencient, and Chris Kahler of Qriously, who believe they can. And we meet the latest robot from Japan's Hitachi that might soon be greeting you in shops. Presented by Rory Cellan-Jones, with BBC tech reporter Chris Baraniuk, and special guest Sarah Golding, chief executive of advertising agency CHI & Partners and incoming president of the ad industry body the IPA.

(Photo: Close-up of the Hitachi EMIEW3 robot, Credit: Toshifumi Kitamura/ AFP/Getty Images).