The number of randomized clinical trials and controlled time series evaluating ACT for a variety of problems is growing. In 2006, only about 30 such studies were known, but in 2011 the number had approximately doubled. The website of the Association for Contextual Behavioral Science states that there were 171 randomized controlled trials (RCTs) of ACT published as of December 2016, and over 20 meta-analyses and 45 mediational studies of the ACT literature as of Spring 2016. Most studies of ACT so far have been conducted on adults and therefore the knowledge of its effectiveness when applied to children and adolescents is limited.