Orton-Gillingham (OG) and Orton-Gillingham–based reading instructional programs are commonly implemented reading programs in the United States.
The OG approach is a systematic, sequential, multisensory, synthetic and phonics-based approach to teaching reading. Explicit instruction is provided in phonology and phonological awareness, sound-symbol correspondence, syllables, morphology, syntax, and semantics. A key characteristic of OG reading instruction is that it is multisensory, involving visual, auditory, and kinesthetic/tactile learning pathways, often referred to as the Language Triangle. Instruction directly teaches language components, is provided systematically and cumulatively, requires mastery and overlearning before students advance to new components, is based on ongoing diagnostic information and assessment, and is individualized to the needs of each student.
Twelve studies that employed quasi-experimental or experimental designs are reviewed in this article. These studies included elementary students, adolescents, and college students. Of the twelve studies, five reported that the OG instruction was more effective than were comparison or control interventions for all measured outcomes, four reported that the OG instruction was more effective for at least one (but not all) outcomes in comparison to other intervention(s), two reported that the alternate instruction was more effective than the OG instruction, and one reported no significant differences once covariates were included. The largest effects were reported for word attack and nonword reading outcomes, with mean effect size of .82, and comprehension outcomes, with a mean effect size of .76.
Following a summary of each study, limitations of the current review and implications for future research and practice are described. Given the small number of studies, the lack of methodological rigor of the existing studies, and the inconclusive findings of the effectiveness of OG programs, additional research is needed before the scientific basis can be established.