To identify bots, the Center used a tool known as “Botometer,” developed by researchers at the University of Southern California and Indiana University.
Previous studies have documented the nature and sources of tweets regarding immigration news, the ways in which news is shared via social media in a polarized Congress, the degree to which science information on social media is shared and trusted, the role of social media in the broader context of online harassment, how key social issues like race relations play out on these platforms, and the patterns of how different groups arrange themselves on Twitter.
It is important to note that bot accounts do not always clearly identify themselves as such in their profiles, and any bot classification system inevitably carries some risk of error. The Botometer system has been documented and validated in an array of academic publications, and researchers from the Center conducted a number of independent validation measures of its results.8
more on fake news in this IMS blog