Berger is author of Contagious: Why Things Catch On, which looks into the science behind word-of-mouth and social transmission and how the same six principles drive contagion, whether its around consumer products and policy initiatives or workplace rumours and YouTube videos.. The tool identifies brands with the ‘most contagious’ social content on Facebook and Twitter, based solely on consumer-to-consumer data. It measures brands’ ability to produce contagious content, as well as to distribute it.

The index delivers a ‘Contagious Score’, an all-in-one metric that evaluates how well a brand’s social media content has resulted in consumer-to-consumer sharing compared with competitor brands. Data provider Shareablee provides public data from Facebook and Twitter to power the tool.

“Sharing content is personal and a uniquely ‘social’ action that is a powerful indicator of what’s resonated with an individual in a meaningful way,” said Jill Sherman, SVP, social strategy, DigitasLBi. “Sharing is markedly different from other social media actions such as commenting, liking, or subscribing, not just in the way it impacts perceptions among personal networks, but in the way it impacts algorithms.

“We now have the ability to assess the value and velocity around consumer-to-consumer sharing and gauge how well content is performing to predict future outcomes.”