Twitter’s policy of shutting down accounts run by ISIS sympathizers is diminishing their reach, according to a new paper from the George Washington University Program on Extremism. Researchers monitored accounts regularly from Aug. 21 to Sept. 21, and sporadically from June to October. Despite the sympathizers’ network of shoutout accounts to help suspended users re-gain their followers, many were not able to regain their same standing after suspension, the study found. “Over time, individual users who repeatedly created new accounts after being suspended suffered devastating reductions in their follower counts,” according to the report. Most accounts monitored by researchers had only 300 to 400 followers, and their interactions were largely limited to other people in the same circle, rather than with new users who might be considered recruits. The study follows Twitter’s announcement that it has suspended more than 125,000 accounts after outcry that the site has become an important source of ISIS recruitment.