Research on Wilson

Wilson

Poor Evidence of Relative Effectiveness

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Summary: A number of studies have been carried out to examine the effectiveness of Wilson programs with struggling readers. It's worth noting that, like Take Flight, Wilson Reading System (but not Wilson Fundations) goes beyond just phonics and includes instruction for vocabulary, morphology, and reading comprehension. Unfortunately, across multiple studies, the Wilson programs often underperformed compared to other phonics programs and business-as-usual controls. I have reviewed 5 studies. Of these, just 20% (one study) had at least one reading measure where Wilson demonstrated a statistically significant, positive effect. Unfortunately, 80% of the studies had at least one reading measure where Wilson performed worse than controls. This is, disappointingly, the highest amount of negative results for any of the phonics interventions I have examined to date, by far.

Wilson Programs Research

Wilson Fundations is an OG-based reading and spelling program that can be used as the Core Classroom or “Tier 1” program in schools, and can also be used for small group intervention (“Tier 2”). It covers phonics, phonemic awareness, fluency, handwriting, and spelling, but not reading comprehension. It is a lengthy program which takes 3 years to complete, with 80 hours of instruction delivered each year, for a total of 240 intervention hours (Wilson 2025).

The Wilson Reading System is an intensive, OG-based intervention delivered for 2-8 hours a week. It is a lengthy program, often taking students several years to complete. In one district-wide study, 21% of students graduated from the program within 3 years (Stamm 2017). The rest had to continue intervention. While intervention hours appear to vary, it seems that 200+ hours of intervention would be quite commonly needed with the WRS program, making it one of the longest intervention programs I have reviewed.

Wilson Research Summarized

I have located 5 research studies of Wilson products which include control groups. In these studies, the average effect size was small to moderate, the findings were usually not statistically significant, other interventions or controls sometimes performed better than Wilson, and in a few measures there were negative effects. In the first study, Young 2001 compared Wilson to classroom instruction for a group of 31 high schoolers. After 28 sessions, they found no statistically significant impacts on reading or spelling measures. For a subset of the children who were given an additional tracing treatment, there were large positive effects on sound spelling, letter-word identification, nonsense word reading, and fluency, and a small effect on spelling. Those with a writing treatment saw smaller effects. Unfortunately in all cases (as is common with small studies), the effects were not significant. Another small study (Reuter 2006) of 26 middle school students with reading deficits carried out a 14 week intervention, with 13 students as a control, and the other 13 receiving a total of ~48 intervention hours of Wilson. No significant differences were found for most measures. The intervention had large positive effects in Word Attack and ORF, and reading comprehension, but these results were not significant. The Word Identification post-test found a large and significant but negative effect for the Wilson group. In a larger scale study of 779 struggling readers,  Torgesen et al. 2007, compared four reading interventions to controls. The four interventions were Corrective Reading, Failure Free Reading, Spell Read PAT, and Wilson Reading System. After 80-93 hours of 1:3 intervention, impacts were assessed one year after the intervention year. For 3rd Graders, Wilson had a small but positive effect as compared to the control group in terms of Nonsense Word Reading, Nonsense Word Fluency, Word Identification, and Sight Words. These results were considered statistically significant. Compared to the other interventions, Wilson performed relatively well on most measures, but was second lowest for Nonsense Word Fluency, and the lowest of the four interventions in Oral Reading Fluency results. For 5th Grade, the results were very mixed. Here, the only significant positive impact Wilson had was in Nonsense Word Reading (medium effect size). Compared to controls, Wilson had a negative impact on Oral Reading Fluency, and this was statistically significant for the students who had struggled the most prior to intervention. None of the interventions in the study resulted in improvements in statewide standardized testing. Based on this study, Evidence for ESSA categorized the effect of Wilson as weak (ESSA, 2025).  Furthermore, Wanzek & Roberts 2012 studied a group of 101 students who had been diagnosed with or had symptoms of dyslexia. After 70 hours of Wilson instruction, there were no significant differences between the Wilson treatment group and the control group. There were moderate but non-significant positive effects on word attack, small but non-significant positive effects on word identification. There was a large but non-significant negative effect on comprehension. In the most recent study Fritts 2016 looked at students identified as having learning disabilities and compared Wilson Fundations and Wilson Reading System to the Direct Instruction program Corrective Reading, as well as a Business-As-Usual condition. The study showed no significant differences between the three programs after 30 hours of delivery, but those receiving Wilson did slightly worse than the others. Those who received DI: Corrective Reading saw the best gains on the NWEA MAP test, though the effect size was small. When adjusted for pre-test scores, those receiving Wilson had the lowest average score on the NWEA post-test.

PedagogyNonGrata carried out a small meta-analysis of Wilson programs, and concluded that while its efficacy was somewhat low across studies, its positive results at the 3rd Grade level in the largest, most scientific study (Torgesen, 2007), were noteworthy.

Casual, observational studies (e.g. Stebbins et al 2012, Duff et al 2015 ) of Wilson programs indicate improvements in some reading measures after 2 years, but because there were no control or comparison groups in these studies, the effects cannot be decisively attributed to Wilson program, just as we could not attribute change in student height over the course of the study to the Wilson program.

Notably, when discussing its alignment to Structured Literacy and the Science of Reading, Wilson does not highlight the scientific research studies which examined its effectiveness. Rather, it focuses on its theoretical alignment to the science of reading. 

My takeaway? I would not reach for Wilson programs to help my child unless I had exhausted several other avenues. Wilson programs, though founded on very solid theoretical principles, often take a long time to complete, and simply do not have strong evidence of effectiveness in practice.

Out of the five studies, only one showed statistically significant gains in any reading measures, these gains were small, and this study had negative results at the fifth grade level. In fact, four of the five studies had at least one measure where Wilson students had worse results than those receiving no intervention. A phonics intervention having negative impacts compared to no intervention is quite rare. This program has the most negative outcomes of any program I have reviewed (as of July 2025).

Can Wilson help some children? Certainly. But the real-world research on Wilson is quite weak. Many of the studies are small, showed that the intervention performed worse than controls on some reading measures, and suggest that the intervention will often take a very long time (upwards of 200 hours). Based on what I have seen from research of other phonics programs, you will likely have greater success with other options, and in a far shorter amount of time.

Research Studies:

Fritts, J. L. (2016). Direct instruction and Orton-Gillingham reading methodologies: Effectiveness of increasing reading achievement of elementary school students with learning disabilities. Dissertation. Northeastern University. Google Scholar

Reuter, H.B. (2006). Phonological awareness instruction for middle school students with disabilities: A scripted multisensory intervention. Dissertation 3251867.  Proquest  |  Google Scholar

Torgesen, J., Schirm, A., Castner, L., Vartivarian, S., Mansfield, W., Myers, D., ... & Haan, C. (2007). National Assessment of Title I. Final Report. Volume II: Closing the Reading Gap--Findings from a Randomized Trial of Four Reading Interventions for Striving Readers. NCEE 2008-4013. National Center for Education Evaluation and Regional Assistance. IES (pdf) | Google Scholar

Wanzek, J., & Roberts, G. (2012). Reading interventions with varying instructional emphases for fourth graders with reading difficulties. Learning Disability Quarterly, 35(2), 90-101. ERIC (pdf) | Google Scholar

Young, C. A. (2001). Comparing the effects of tracing to writing when combined with Orton-Gillingham methods on spelling achievement among high school students with reading disabilities. Dissertation. The University of Texas at Austin. Google Scholar 

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This Research Summary is a work in progress.

Leave me a comment if you know of other studies that I could include!