The What Works Clearinghouse (WWC) is an organization established in 2002 that is charged with producing user-friendly guides for educators on effective instructional practices. Many of you also are likely familiar with NIFDI's reservations and concerns with the procedures and reports the WWC publishes, which are documented on our website.
That said, a recent report published by the What Works Clearinghouse details the effectiveness of Spelling Mastery for students with learning disabilities. Spelling Mastery, a Direct Instruction program designed for students in grades 1-6 to teach phonemic, morphemic and whole-word strategies, demonstrated "potentially positive" effects in writing with students with learning disabilities.