September 2020: Differentiated Literacy Instruction: Boondoggle or Best Practice?

Puzio, K., Colby, G. T., & Algeo-Nichols, D. (2020). Differentiated literacy instruction: Boondoggle or best practice? Review of Educational Research, 90(4).

Summary by Sarah Fishstrom and Sharon Vaughn

Study Background

Schools in the United States are diverse with regard to home resources, culture, academics, and linguistics. This diversity is an asset, but also contributes to a range of educational needs—perhaps most importantly in the area of reading. With increasingly diverse student needs along with heightened pressure for schools to meet rigorous standards, many scholars and policymakers have often considered differentiated instruction as a potential pathway for improving outcomes for all students (e.g. Higher Education Opportunity Act, 2008; National Association for Gifted Children, 1994). However, there is conflicting evidence regarding the extent that teachers differentiate instruction (e.g. Baker & Zigmond, 1990; Cordray et al., 2013) and whether differentiation works. Delisle (2015) called differentiation “a boondoggle of massive proportions” (p. 28), explaining that it is nearly impossible to teach to a diverse range of learners and the term itself, differentiate, is unclear and leaves teachers without guidance on how to do “it.”

To address the question of whether differentiated literacy instruction works, Puzio and colleagues (2020) recently conducted a meta-analysis on the effects of differentiated literacy instruction in general education classrooms, commonly referred to as Tier 1 within frameworks that utilize multi-tiered systems of support. As practitioners and policymakers are urged to use evidence-based practices, a meta-analysis can provide a key source of information as it employs statistical techniques to synthesize results from several empirical studies into a quantitative estimate known as an effect size (Petticrew & Roberts, 2008). Therefore, the findings of this meta-analysis can help inform educational leaders about the effects of differentiated instruction in the general education classroom and it can, more broadly, help schools realize their goals of successful differentiation. 

What is Differentiated Literacy Instruction?

Differentiation holds promise for meeting the range of learning needs in the classroom, but it is complicated and often considered vague. The authors’ theoretical framework underlying differentiation is based on Vygotsky’s Zone of Proximal Development (1978), which states that students have a range of learning potential, that learning is flexible, and that with “just enough” scaffolding and support students will accomplish more than they could independently. In order to better understand the term differentiation, Puzio and colleagues break it down into interactional differentiation and designed differentiation, which is further broken down into subcategories as follows:

Interactional differentiation

Teacher’s role:

The teacher adapts their instruction based on students’ performance while they work with texts and tasks.


As students work in small groups, a teacher realizes that one group cannot accomplish the task in the set time and provides the students with extra time.

When working with a student individually, a teacher provides a review of the lesson.   

Designed Differentiation

Teacher’s role:

The teacher proactively plans ahead with many levels of supports and scaffolding for texts and tasks, knowing ahead of time what her students will need.


The teacher prepares three different versions of the daily text or a reading assessment.

  • Content Differentiation
  • Teacher’s role:
  • The teacher adjusts the content that students learn
  • Examples:
  • Students in a classroom reading different books that vary in text complexity or student receive extra explicit decoding instruction while others independently read.
  • Process Differentiation
  • Teacher’s role:
  • The teacher provides students opportunities to learn is different ways that includes task and tool differentiation.
  • Examples:
  • Students complete different projects, work, or activities (task differentiation).
  • Some students might use text-to-speech software, paragraph starters, or sentence frames (tool differentiation).
  • Product Differentiation
  • Teacher’s role:
  • The teacher provides a range of options for presenting work (e.g., oral, written).
  • Example:
  • Multiple options are provided for a culminating project (e.g., provide a speech, write an essay) or a composition (e.g., write a new ending to a story or essay analyzing a character).

Previous Reviews

Two reviews have been conducted on differentiation, but Puzio et al., (2020) contend that they are not systematic, discipline specific, or quantifiable:

  • Tomlinson et al. (2003) examined evidence from across disciplines and concluded that in-service and preservice teachers typically view learner differences as a problem and findings revealed that differentiation was provided ineffectively.
  • Subban (2006) analyzed seven studies from a range of disciplines and found a positive effect of differentiation on classroom instruction and learning. 

Purpose and Research Questions

In the absence of previous systematic reviews that were literacy specific, the purpose of this review was to help synthesize empirical findings of Tier 1 literacy differentiation.

Two research questions were asked:

  1. Do Tier 1 differentiation programs affect student literacy achievement and, if so, to what degree?
  2. Do any moderators (e.g., grade, outcome, type of differentiation) help explain this effect?


Studies were included if they met the following criteria: (a) the focus was differentiated literacy instruction; (b) the instructor was the general education teacher; (c) the effects of literacy differentiation were reported; (d) literacy outcomes were included; (e) design allowed for causal inferences; (f) instruction took place in a regular classroom setting; (g) control or counterfactual condition was included; and (h) studies were available in English (but conducted in any country).

Eighteen studies met inclusion criteria and within these studies there were 25 unique cohorts. Overall, the majority of studies (94%) were conducted in elementary school classrooms and included a variety of backgrounds and cultures.

  • Five studies utilized Individualized Student Instruction (ISI) which uses computer software to analyze literacy assessment data and create individual reading plans.
  • Four studies utilized School Wide Enrichment Model in Reading (SEM-R) which is based on student choice; Students choose what they will read and how they will present their understanding.
  • Two studies used Integrated Curriculum Model of William and Mary Language Arts Program (ICM/WMLA) which is designed to engage gifted students in cross-disciplinary ways with advanced multicultural texts.
  • One study reported on using the following approaches to literacy differentiation: Literature circles, Writers workshop, Exemplary Model of Early Reading Growth and Excellence (EMERGE), Dyad Reading, Measures of Academic Progress (MAP), and CLEAR.

Key Findings

What is the effect of differentiated literacy instruction in a general education classroom on reading outcomes?

Research Question 1

The results:

  • Very small, positive, statistically significant effects for comprehension outcomes (g=.09; p=.034)
  • Small, positive, statistically significant effects for letter-word reading outcomes (g=0.20; p = .014)
  • Large, positive, statistically significant effects for writing outcomes (g=1.19 winsorized to .96; p < .001), which are cautioned due to relying on researcher-developed measures that often result in higher effect sizes (Lipsey et al., 2012)
  • Of the 18 studies and 25 cohorts, the combined mean effect size in hedges g was 0.13 (p = .002), indicating a small, positive effect from Tier 1 literacy differentiation instruction
  • Positive, but statistically insignificant effects for fluency outcomes (g=.07; p=3.07) and vocabulary outcomes (g=0.05; p = .611)

Research Question 2

Could not be addressed because of an overall homogeneity of effect sizes.

Overall, the combining literacy outcomes yielded a small, positive increase in literacy achievement as compared to teachers maintaining business as usual, which likely included some differentiation. Differentiated literacy instruction had the greatest effect with regard to writing outcomes, followed by small effects for letter-word (decoding) outcomes and very small effects for comprehension outcomes. This could be interpreted as programs that promote instructional differentiation appear to work well for student outcomes with regard to writing and letter-word instruction and less so with regard to comprehension instruction and outcomes. However, this finding should be interpreted with caution because only three studies examined the effects on writing outcomes, and all of these studies used researcher-developed measures of writing, which are consistently found to yield greater effect sizes than standardized measures (Scammacca et al., 2015). Additionally, differentiation programs have no statistically significant effect on fluency or vocabulary outcomes as compared to business as usual.

Implications for Practitioners

Within the multi-tiered system of supports framework in schools, the Tier 1 instruction provided within general education has a vital role to play in the prevention of reading difficulties. In fact, one of the primary roles of Tier 1 instruction is to reduce the number of students inappropriately receiving special education through prevention and identification (Fuchs et al., 2010). In providing effective Tier 1 literacy support, this could also reduce the overrepresentation of children of color from low-income households in special education, which can have consequences (McLaughlin, 2006). In order to provide effective Tier 1 instruction, differentiation seems to be essential. Fuchs et al. (2010) state that differentiation in the general education classroom is “recognized as both critically important and difficult to accomplish” (p. 312). Puzio et al.’s (2020) meta-analysis shows modest evidence that supporting teachers with literacy differentiation can improve students’ literacy outcomes. However, further guidance is needed on how to best teach differentiation to educators and how to most effectively implement it with diverse students. Resources for how to differentiate can be found here and here.


As with many syntheses, this one does not adequately describe the interventions so that education might better understand how teachers specifically implemented differentiation in their general education classrooms. Although it appears differentiation programs improved literacy outcomes, the details are missing. Treatment fidelity was only measured in a few studies and the business-as-usual condition lacked detailed explanation. Lastly, it should be noted that the majority of studies were quasi-experimental, meaning students were in their “natural” classrooms and had not been randomized by the researchers, which is considered the “gold standard” (What Works Clearinghouse, 2020). Additional rigorous research is required to better understand the effects of differentiation and the conditions under which it is particularly effective.


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