study released last week by the University of Southern California and Indiana University claims that as many as 48 million Twitter accounts are bots.

The study used more than 1,000 different features to find and identify bot accounts across Twitter. It is estimated that somewhere between 9% and 15% of Twitter’s active monthly users are bots or fake accounts. Twitter recently stated that their userbase consists of approximately 319 million active monthly users, based on those figures 28.7 million to 47.9 million of Twitter’s users are bot accounts.

This estimate is significantly higher than Twitter’s own analysis of bots on the platform. The company has previously stated that 8.5 percent of its active monthly users are automated accounts. Twitter’s estimate puts the number of bots at just over 27 million accounts while the study states that the number is at least 28.7 million bots but could be as high as 47.9 million.

The university researchers even stated that their 15% figure is a “conservative estimate” and that the number could be much higher. Some of the more complex bots can fool many people into believing that they’re real users, skewing the results to some degree.

Bot accounts on Twitter are often used to automatically follow other accounts or retweet posts from particular users or those that use certain phrases. Many exist strictly to advertise to Twitter’s human users.

Twitter has had issues with bots in the past, another study from the University of Southern California found that 19% of election-related tweets this year came from bot accounts. Twitter has yet to publicly respond to the study or state whether they will attempt to combat the use of bots on their platform.

Lucas Nolan is a reporter for Breitbart News covering issues of free speech and online censorship. Follow him on Twitter @LucasNolan_ or email him at lnolan@breitbart.com