A Twitter research study by the University of Southern California has revealed that approximately 15 15% of the social media platform's active users are software controlled bots.
"Our data collection focused on active users producing content in English, as inferred from profile meta-data. We identified active users by monitoring a large Twitter stream, accounting for approximately 10% of public tweets, for 3 months starting in October 2015." said the University of Southern California when explaining their methodology in compiling the report.
This report comes after Twitter itself revealed a lower number of active bots exist on the platform as the University of Southern California went on to explain "In a 2014 report by Twitter to the US Securities and Exchange Commission, the company put forth an estimate that between 5% and 8.5% of their user base consists of bots. We would like to offer our own assessment of the proportion of bot accounts as measured with our approach. Since our framework provides a continuous bot score as opposed to a discrete bot/human judgement, we must first determine an appropriate bot-score threshold separating human and bot accounts to estimate the proportion of bot accounts."
Given that Twitter has previously reported that it has 319 monthly active users this means that roughly 48 million of these monthly active users are bots.
You can download the University of California's full report titled "Online Human-Bot Interactions: Detection, Estimation, and Characterization" here.