|In the 2012 study, Large-scale Randomized Controlled Trial with 4th Graders Using Intelligent Tutoring of the Structure Strategy to Improve Nonfiction Reading Comprehension, researchers examined the effects of the web-based tutoring program, Intelligent Tutoring of the Structure Strategy (ITSS), on the reading comprehension of fourth-grade students in language arts classrooms. ITSS is a one-on-one, web-based intelligent tutoring system which models a "structure strategy" technique, provides practice opportunities, and gives immediate feedback to students. The analysis included 1,875 to 2,371 fourth-grade students from 100 to 117 classrooms in Pennsylvania elementary schools. Study authors assessed the effectiveness of ITSS by comparing the reading comprehension of students in ITSS classrooms with students in comparison classrooms. The study is a well-implemented randomized controlled trial, and the research meets WWC evidence standards without reservations.