Does Raz-Plus improve reading growth? What ESSA Tier 2 studies show

Reading achievement remains a priority for schools as educators work to strengthen foundational skills, address literacy gaps, and help every student progress. With many literacy resources available, school and district leaders need credible evidence to understand which solutions are associated with meaningful student outcomes.

Two efficacy studies offer evidence that consistent classroom implementation of Raz-Plus^® from ExploreK12^TM is associated with stronger reading growth. Together, the ESSA Tier 2 studies included 7,831 first- and third-grade students. In both studies, students in classrooms using Raz-Plus demonstrated significantly greater reading growth than students in comparison classrooms.

The findings also point to benefits for students with different instructional needs, including first-grade students who began the year below the 25th percentile, third-grade students in high-poverty schools, as well as third-grade students performing at or above grade-level expectations.

Key findings from the research

Two ESSA Tier 2 studies included 7,831 students
First-grade students gained the equivalent of approximately 1.6 additional weeks of reading growth
Third-grade students gained the equivalent of approximately 4.4 additional weeks of reading growth
Students below the 25th percentile demonstrated the strongest gains in first grade
Third-grade students exceeded expected national growth rates
Positive outcomes were observed in high-poverty schools and among advanced readers

What the Raz-Plus efficacy research examined

The two Raz-Plus studies focused on different grade levels and student populations, but both examined the relationship between classroom implementation and reading growth.

First-grade reading growth over 16 weeks

The first-grade study included 4,602 students across 123 schools and 267 classrooms. Researchers compared outcomes for:

1,870 students in classrooms with high, consistent Raz-Plus implementation
2,732 students in classrooms with minimal Raz-Plus usage

Reading achievement was measured with the NWEA MAP Growth Reading assessment between the fall and winter testing periods. The results were standardized to a 16-week growth window.

Researchers used hierarchical linear modeling to account for factors at the student, classroom, and school levels. They also examined whether outcomes differed based on students’ initial levels of academic risk.

Third-grade reading growth across 15 states

The third-grade study included 3,229 students from 164 classrooms across 15 U.S. states during the fall 2025 semester. Researchers compared:

82 classrooms using Raz-Plus
82 baseline-matched classrooms that did not use Raz-Plus

The study measured changes in students’ RIT scores between the fall and winter assessment periods. Researchers controlled for demographic and school-level differences and examined overall growth, performance relative to national norms, outcomes in high-poverty schools, and results for students at different achievement levels.

In this study, Raz-Plus was implemented regularly as a teacher-directed supplemental resource.

What does ESSA Tier 2 evidence mean?

Both studies meet Every Student Succeeds Act (ESSA) Tier 2 standards for Moderate Evidence. Each used a well-designed quasi-experimental design with baseline-equivalent or carefully matched treatment and comparison groups.

Unlike a randomized controlled trial, a quasi-experimental study does not randomly assign participants to groups. Instead, researchers use comparison methods and statistical controls to account for pre-existing differences and evaluate whether outcomes are associated with the program being studied.

Because neither study randomly assigned students or classrooms, the findings should be described as evidence of an association between Raz-Plus implementation and reading growth rather than definitive proof of causation. However, both studies found statistically significant positive effects after accounting for relevant student, classroom, school, and demographic factors.

Students using Raz-Plus demonstrated greater reading growth

Across both studies, students in Raz-Plus classrooms achieved significantly greater reading growth than students in comparison classrooms.

First-grade students achieved stronger reading gains

Over the standardized 16-week period, first-grade students in classrooms with high, consistent Raz-Plus implementation gained an adjusted average of 8.75 RIT points. Students in classrooms with minimal Raz-Plus usage gained an adjusted average of 8.07 RIT points.

That difference represented approximately 1.6 additional weeks of reading instruction for students in the high-implementation group.

Students using Raz-Plus also exceeded typical national NWEA MAP Growth expectations by 10%. These results suggest that consistent implementation was associated not only with greater growth than minimal usage, but also with growth beyond national expectations.

Third-grade students gained the equivalent of 4.4 additional weeks of reading growth

Third-grade students in Raz-Plus classrooms gained an average of 7.41 RIT points during the fall-to-winter study period. Students in matched comparison classrooms gained an average of 6.05 RIT points.

The resulting 1.36-point growth advantage was equivalent to approximately 4.4 additional weeks of reading growth within one semester. This advantage remained statistically significant after researchers controlled for demographic and school-level factors.

The third-grade Raz-Plus cohort achieved 1.27 times the expected national norm growth for the fall-to-winter period.

Together, the findings indicate that students in Raz-Plus classrooms demonstrated stronger growth than their respective comparison groups and surpassed national growth expectations.

Supporting students who need reading acceleration

The first-grade findings were particularly notable among students who began the study with the greatest academic risk.

First-grade students below the 25th percentile experienced the greatest benefits

Students entering the year below the 25th percentile demonstrated the largest gains associated with Raz-Plus implementation. These students achieved an instructional advantage equivalent to approximately 2.6 additional weeks compared with similar students in minimal-use classrooms. The result is especially relevant for educators working to identify literacy needs early and provide differentiated supplemental instruction before gaps become more difficult to address.

The first-grade study suggests that consistent Raz-Plus implementation may be particularly valuable for students beginning the year substantially below national achievement benchmarks.

Supporting growth across the achievement spectrum

Although intervention is often associated with students performing below expectations, educators also need ways to support continued growth among students who are meeting or exceeding benchmarks.

Third-grade findings showed positive results for students at higher achievement levels

The third-grade study examined outcomes across the achievement spectrum. Students identified as Tier 1 and gifted demonstrated significantly greater reading growth than similar students in comparison classrooms.

These results suggest that regular, teacher-directed Raz-Plus implementation was associated with effective upward differentiation, providing instructional value for students who were already performing at higher levels.

The findings reinforce the importance of differentiation that supports striving readers without limiting opportunities for on-level and advanced students to continue progressing.

What the findings reveal about literacy equity

Schools serving high-poverty communities may face additional challenges in providing equitable access to instructional resources and learning opportunities.

Students in high-poverty schools demonstrated substantial growth

The third-grade study examined schools where more than 75% of students qualified for free or reduced-price lunch.

In these schools, students using Raz-Plus gained an average of 7.7 RIT points. Students in matched non-user classrooms gained an average of 5.4 RIT points.

The Raz-Plus group's growth also exceeded the national average.

These findings suggest that regular implementation of Raz-Plus can be a valuable component of supplemental literacy instruction in under-resourced school communities.

Consistent implementation matters

A common theme across both studies was the role of regular classroom implementation.

The first-grade study compared classrooms with high, consistent Raz-Plus implementation with classrooms reporting minimal usage. The third-grade study compared classrooms that regularly used Raz-Plus as a teacher-directed supplemental resource with matched classrooms that did not use the program.

Neither study was designed to isolate which individual aspects of Raz-Plus produced the observed results. However, the findings indicate that consistent, teacher-directed implementation was associated with stronger reading growth than minimal or no use.

For educators and administrators, this distinction matters. Selecting a research-backed resource is only one part of an effective literacy strategy. Schools must also consider how that resource will be integrated into instruction and used consistently to support students’ needs.

What these findings mean for educators and leaders

For classroom teachers

The findings suggest that consistent use of Raz-Plus can support differentiated supplemental reading instruction for students with varying reading abilities and needs.

For teachers, the research reinforces the value of:

Using student data to identify instructional needs
Providing regular opportunities for reading practice
Differentiating support based on students’ starting points
Using supplemental resources consistently as part of classroom instruction
Monitoring growth to determine where students need added support or challenge

For literacy specialists and interventionists

The first-grade findings are particularly relevant for professionals supporting students below expected achievement levels. Students beginning below the 25th percentile experienced the greatest instructional advantage associated with Raz-Plus implementation.

Literacy specialists and interventionists can use evidence like this to:

Evaluate supplemental resources
Plan targeted support
Monitor whether striving readers are making sufficient progress

For school and district leaders

The two studies provide school and district leaders with ESSA Tier 2 evidence across multiple grades and student populations.

When reviewing literacy resources, leaders can consider:

The quality of the research design
Whether the research includes appropriate comparison groups
The number and diversity of participating students and schools
Whether the findings apply to their instructional priorities
The implementation conditions associated with positive outcomes
How student growth will be measured locally

Explore the research behind Raz-Plus

Read the full efficacy studies to learn more about the research design, participating students, implementation criteria, and student outcomes. Then start a free trial of Raz-Plus or reach out to see how it can support differentiated supplemental literacy instruction in your classroom, school, or district.

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Frequently asked questions about Raz-Plus efficacy

Why does reading growth evidence matter in elementary years?

Reading growth is an important indicator of student progress during the elementary years, when foundational literacy skills are developing. While proficiency measures show whether students meet grade-level expectations, growth measures reveal how much students improve over time. Together, these measures help educators identify learning needs, monitor progress, and evaluate the effectiveness of literacy instruction and reading programs.

Does Raz-Plus improve reading growth?

Two quasi-experimental studies found that students in classrooms using Raz-Plus demonstrated significantly greater reading growth than students in comparison classrooms.

First-grade students in high-implementation classrooms gained an adjusted average of 8.75 RIT points, compared with 8.07 points among students in minimal-use classrooms. Third-grade students gained an average of 7.41 RIT points, compared with 6.05 points among students in matched classrooms that did not use Raz-Plus.

Is Raz-Plus supported by ESSA evidence?

Yes. Both the first-grade and third-grade studies meet ESSA Tier 2 standards for Moderate Evidence.

Does Raz-Plus support striving readers?

The first-grade study found the greatest benefits among students entering the year below the 25th percentile. These students achieved an instructional advantage equivalent to approximately 2.6 additional weeks compared with similar students in minimal-use classrooms.

Can Raz-Plus support students who are already performing well?

The third-grade study found significantly greater growth among Tier 1 and gifted students in Raz-Plus classrooms compared with similar students in matched comparison classrooms.

How quickly did students demonstrate measurable growth?

The first-grade study measured growth over a standardized 16-week period. The third-grade study examined growth during a single fall-to-winter semester.

How did students in high-poverty schools perform?

In schools where more than 75% of students qualified for free or reduced-price lunch, Raz-Plus students gained an average of 7.7 RIT points compared with 5.4 points among students in matched comparison classrooms.