ABSTRACT
Religious radicalism is a threat of which many parties, including schools, should be alert because students are vulnerable to thought infiltration. Many studies found radical thought among students. However, it indicates only the phenomenon existing without yielding expedient and efficient preventive attempt. Therefore, the author developed “SIDEDI” application early detection instrument of radical thought phenomenon for Senior High School students that can be accessed online through Playstore. This research and development adapts Walter Dick and Lou Carey's ten development stages. The result shows that there are two applications designed separately for teachers and students. Student (SIDEDI) application was designed to indicate and to answer questions. Meanwhile, the code to access class and question was designed for teacher application.
