Stern Professors Develop New Method to Measure Influence in Social Networks

In a new paper, recently published in Science, Sinan Aral, a Stern School of Business assistant professor of information, operations, and management sciences, and his co-author Dylan Walker, a research scientist at Stern, present a new method to measure influence and susceptibility in social networks.

Today, finding “influentials” is all the rage. Companies such as Klout are trying to measure “influence scores” for people in social media networks like Facebook and Twitter, and brands are using this information to target them with advertising. Beyond marketers, parents are interested in whether their children’s peers influence education outcomes; managers are interested in whether workers’ colleagues influence their productivity; and policymakers are interested in whether risky behaviors, such as drug abuse, spread as a result of peer-to-peer influence.

“The important contribution of our method,” explains Aral, “is that it avoids known biases in current methods, such as homophily bias, which means that we tend to make friends with people like ourselves. For example, if two friends adopt a product or behavior one after the other, current methods have a hard time distinguishing whether it is because of peer influence or if the friends simply have similar preferences and thus behave similarly.”

Aral and Walker used their method to measure influence and susceptibility in the adoption of a commercial movie application on Facebook among 1.3 million users. Their findings included the following: men are more influential than women; women influence men more than they influence other women; and married people were the least susceptible to influence in the decision to adopt the product they studied.

This new method, say the researchers, has a wide variety of applications, such as developing effective targeting strategies to spread products or behaviors in society.

“This is certainly important for targeted advertising and viral marketing of products, but can also be used to affect social good,” explains Aral. “We are now working on applying the same science to promote HIV testing in Africa and other positive behaviors, including exercise and political awareness.”

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