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What Percentage of Students Can Succeed With Just Core Instruction?

In this article, I wanted to continue our series on whether or not 95% of students could learn how to read. The figure 95% of students can learn how to read originates from two literature reviews. The first one was published by Patricia Mathes and Carolyn Denton in 2002 and the second by Joseph Torgesen in 2009. Both literature reviews seem to suggest that more than 95% of students could learn how to read (usually defined by reaching the 30th percentile on the Woodcock Reading assessment), provided they were provided with 80 hours plus of small group, tier 3 instruction. Last week, I re-analyzed their results and specifically controlled for the impact of systematic phonics tier 3 instruction, within the studies covered by Torgersen and Mathes. I found that if struggling readers were given 80 hours of tier 3 systematic phonics instruction, 97.5% of all students within the overall class could learn how to read on grade level.

However, there is a catch to all three literature reviews. They were all based on the idea that only 18% of readers in the school started below the 30th percentile. However, the NAEP basic marker is roughly the 25th percentile and currently 37% of students in the USA are reading below this benchmark. This means that in order for it to be a realistic goal for policymakers to suggest that 95% of students can learn to read, we would need to show that up to 82% of readers can get to grade level based on core instruction alone. Unfortunately, there is no evidence available to answer this question because the vast majority of reading studies use mean difference and standard deviation, to measure results not the percentage of students on grade level. 


Why don't we see academic research using "grade level benchmarks'' as a metric?  

It’s a poor scientific metric because it uses an arbitrary cut off mark that is inconsistent across populations, tests, and contexts.It does not account for students who are far above grade level, nor does it account for if students are only slightly above grade level. Conversely, an effect size is primarily used to measure the magnitude of effect that a treatment provides to one group of students over another. For example, we could have 100% of students in one class, on grade level and 0% in another, but the mean difference could still be only 1%. The outcome would look significant; however, in reality, this difference could be entirely statistically insignificant. That said, the percentage of students reading on grade level is more commonly used in non-academic circles. It’s easier for both educators and politicians to understand. Consequently, policies are often based on metrics related to such measurements. 


This disparity means, that despite the fact that the percentage of students reading on grade level is likely a widely discussed metric, amongst policymakers and educators it is difficult to find a meta-analysis or even a rigorous analysis of the subject. The literature reviews currently on this topic, were all based on small-scale, tier 3 intervention studies. I wanted to answer the question, of what percentage of students could learn to read on grade level, from just core instruction alone? 

To answer this question, I went through the database of studies that we have gathered for Pedagogy Non Grata. First I eliminated all studies that were not based on purely core instruction. Then I looked through the studies that showed effect sizes of .40 or higher (I chose this cutoff point, as I was hoping to measure the potential result and not the average result. In total, 28 studies that met this inclusion criteria. However, only 11 studies included the percentage of students at grade level. Two of these studies were RCTs, four of these studies were quasi-experimental, and five of these studies did not use control groups. After this I found two additional studies, one RCT was sent to me, by Dr. Rachel Schechter, who has been collaborating with me on this project. The final study was included in the 2009 literature review (Torgesen 1999), in which the control group received systematic phonics as part of their core instruction. In total, I found 13 core instruction studies, in which the percentage of students at grade level was measured. Three of these studies looked at systematic phonics, and ten of these studies looked at just providing additional supplementary phonics instruction to business-as-usual instruction. I would have liked to also look at balanced literacy studies on this topic. However, I was unable to find any, as most balanced literacy studies only focus on tier 3 instruction.

On average 82.92% of students reached grade level in these studies. However, I have broken down these results more in the following graph.

I think the most important fact to notice about these results, is that there appears to be a linear relationship between the percentage of students at grade level and the age of the students. The older the students were, the less effective the study treatment was at bringing students to grade level. This suggests that early phonics instruction is key to getting students to read on grade level earlier in their elementary years and then hopefully stay on grade level as they age. This seems to be in line with the Colby Hall 2022 meta-analysis, which showed that reading interventions were twice as successful in grade 1, compared to grade 3. While these results cannot be directly extrapolated to a state level, Dr. Schechter and I agree that they suggest that early phonics instruction, starting in kindergarten, is necessary, if we want 95% of students to be reading on grade level. 


While the above results show the percentage of students on grade level in these phonics studies, they don’t account for how many students were on grade level to begin with. Six of these studies had control groups that also measured the percentage of students on grade level. On average the control groups had 37% of students reading on grade level, on the end of the year post tests and the treatment groups performed 46.76% better. Five of these studies measured the difference in the percentage of students on grade level at the beginning of the study compared to the end. Of these 5 studies, there was a mean improvement of 37.2%. This would seem to suggest that between 37% and 53% of differences could be predicted by whether or not the students received phonics instruction (median 41.98%), at least for grades k-3. Of course, it should be caveated that this metric is based on a small number of studies, using an imprecise measurement. 


In order to get to 95%, we need to first get to 82%.  This analysis confirms that yes,  we can get 82% of students reading at grade level from evidence-based core instruction alone. On average 82.92% of students were reading at grade level by the end of the core instruction in the phonics studies examined. However, it is important to note that, we found no scientific support for getting 82% of students reading on grade level if phonics instruction started after grade 1. This seems to suggest the importance of starting phonics instruction in Kindergarten or earlier.  I will keep my eyes out for new research reports that provide evidence for starting later. 


Written by Nathaniel Hansford and Dr. Rachel Schechter of LXD Research

Last Edited 2023-05-16



Torgesen, J. (2009). Preventing Early Reading Failure and its Devastating Downward Spiral. National Centre for Learning Disabilities.


Torgesen, J.K., Wagner, R.K., Rashotte, C.A., Rose, E., Lindamood, P., Conway, T., et al. (1999). Preventing reading failure in young children with phonological processing disabilities: Group and individual responses to instruction. Journal of Educational Psychology, 91, 579-593. 


Mathes, P. G., & Denton, C. A. (2002). The prevention and identification of reading disability. Seminars in Pediatric Neurology, 9(3), 185–191.


Schechter, R., Macaruso, P., Kazakoff, E.R. and Brooke, E. (2015). Exploration of a blended learning approach to reading instruction for low SES students in early elementary grades. Computers in the Schools, 32, 183–200.


Schechter, R. (2022). 95 Phonics Core Program. LXD Research.


Hall, C., Dahl-Leonard, K., Cho, E., Solari, E.J., Capin, P., Conner, C.L., Henry, A.R., Cook, L., Hayes, L., Vargas, I., Richmond, C.L. and Kehoe, K.F. (2022), Forty Years of Reading Intervention Research for Elementary Students with or at Risk for Dyslexia: A Systematic Review and Meta-Analysis. Read Res Q.


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories RCT Study. First Grade: Arkansa. 


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: First Grade, California. 


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: First Grade, Georgia. 


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: Kindergarten, Idaho (1) 


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: Kindergarten, Idaho (2) 


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: Kindergarten, Florida 


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: Kindergarten, West Virginia


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: Grade 1, Michigan. 


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: Kindergarten, South Carolina


Hansford, N,. McGlynn, S & King, J. (2023). Secret Stories Study: Kindergarten, Texas 

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