Turner-2008

Commentary:

A systematic review to empirically assess the effectiveness of OG and OG-based reading instruction designed to improve reading and reading-related outcomes across the grade span (K–16) is critically important. This review has serious implications for education stakeholders, including policymakers, administrators, teachers, tutors, parents, and children.

This type of reading instruction is, according to the authors, specifically requested by parents and professionals for a significant number of students receiving special-education services. The OG approach uses the language triad of senses (visual, auditory, and kinesthetic–tactile). This, combined with the widespread acceptance of and enthusiasm for OG and OG-based reading instruction that is based on anecdote, rather than evidence, highlights the importance of a systematic review that is methodologically sound and distinguishes evidence according to internal validity (Shadish, Cook, & Campbell, 2002).

The review authors’ call for additional, higher-quality research before the efficacy of OG and OG-based reading instruction can be established scientifically is supported by their methodologically sound systematic review. A systematic review is a series of procedures that limit bias in the collection, appraisal, analysis, and interpretation of studies on a topic—it may or may not include a meta-analysis (Chalmers & Altman, 1995). While conducting this review, the authors searched the literature using both electronic and hand searches
(Cooper, 1998), specified pertinent inclusion criteria, prior to searching the literature, which differentiated among study designs, coded studies to limit author bias, estimated intervention impacts using effect sizes (Lipsey & Wilson, 2001), and systematically conducted a narrative synthesis of intervention impacts across studies. Even though the authors excluded grey literature from their searches, they acknowledged this omission,
along with the implications in the study-limitation section of the review.

Although a statistical synthesis, or meta-analysis, can provide a more efficient and succinct summary of intervention impacts, the authors rightly choose a narrative synthesis, given the small number of studies and substantial variation in OG-based interventions, participants, outcome, and so forth. Under these conditions, a meta-analysis may be inappropriate and no more revealing than a narrative synthesis; although, in
the latter, authors should be disciplined in synthesizing information and exhibit extra caution in introducing bias (Petticrew & Roberts, 2006)….