Leveled Literacy Intervention – Intervention that WORKS

WWC_CheckmarkProven effective WWC_Checkmark Small student-teacher ratios
WWC_Checkmark Explicit daily instruction WWC_Checkmark Original, high-interest, diverse fiction and nonfiction books
WWC_Checkmark Systematic lesson structure designed for success WWC_Checkmark Embedded professional learning
WWC_Checkmark Daily phonics/word work  

What is Leveled Literacy Intervention?

Leveled Literacy Intervention (LLI) is an intensive, small-group, supplementary literacy intervention for students who find reading and writing difficult. The goal of LLI is to lift the literacy achievement of students who are not achieving grade-level expectations in reading. The LLI systems are designed to give students the boost they need to achieve literacy success.
LLI Systems Small-Group Size Daily Instruction Success in Weeks 
K, 1, 2
F&P LLI 3 Circles orange green blue

Teacher-to-student ratio

30-minute lessons,
5 days per week

14-18 weeks
of explicit, direct instruction

3, 4, 5+
F&P LLI 3 Circles Red Yellow Purple

Teacher-to-student ratio
45-minute lessons,
5 days per week

18-24+ weeks 
of explicit, direct instruction


Evidence Based Research

RESEARCH BASE: Leveled Literacy Intervention, Grades K–2 (Levels A–N)

The development of LLI rests on what research has established about how children learn to read, and what works best with struggling readers.

RESEARCH BASE: Leveled Literacy Intervention, Grades 3–5+ (Levels L–W)

The development of LLI Red, Gold and Purple rests on 15 principles, grounded in research, on which the LLI Systems are based.


Classroom-Based Efficacy and Research


*The What Works Clearinghouse (WWC) systematic review of the evidence from independent research studies found Leveled Literacy Intervention to have POSITIVE EFFECTS on general reading achievement.  

WWC: Showing Positive Impacts For Beginning Reading. LLI Reading Achievement ++. Read full WWC report at whatworks.ed.gov.

  • Rating of Effectiveness:

Positive Effects: STRONG evidence of a positive effect with no overriding contrary evidence.

In the two studies that reported findings, the estimated impact of LLI on outcomes in the general reading achievement domain was positive and statistically significant for two studies, both of which meet WWC group design standards without reservations.

For the combined K-2 sample, the WWC found a statistically significant positive difference between the intervention and comparison groups. This result was large enough to be considered substantially important. The WWC characterizes this study finding as a statistically significant positive effect. The WWC-calculated effect size was large enough to be considered substantially important.

Summary of findings - meets WWC group design standards without reservations. Improvement was statistically significant for general reading achievement and reading fluency.F&P BAS Domain average for general reading achievement (Ransford-Kaldon et al., 2010). Effect size 0.35. Statistically significant.

Summary of settings and samples. 33% black, 29% white, 38% not specified. 51% Hispanic, 49% not Hispanic. 53% male, 47% female. 84% on free and reduced price lunch. 22% English Learners.


*Evidence for ESSA’s review of the independent research studies on LLI found STRONG evidence of effectiveness for students.

Evidence for ESSA: LLI receives strong rating for effectiveness. 2 Studies, 566 students, average effect size +0.13. Read more at evidenceforessa.org.

*Robert Slavin, Director of the Center for Research & Reform in Education at Johns Hopkins University, a co-founder and Chairman of the Board of the Success for All foundation and co-creator (with colleagues) of Evidence for ESSA, named LLI in a recent NPR article as a well-documented program to help children gain learning ground.


LLI has been evaluated in two qualifying studies. In one, in rural and suburban Georgia and New York, students were randomly assigned to LLI or control conditions. Across 5 DIBELS scales, the average effect size was +0.17, with significant differences on Non-Word Fluency and Oral Reading Fluency. In a second study in Denver, there were very positive outcomes on the DRA2 in kindergarten but not in first or second grade, for a significant but small meaningful effect size of +0.10. Averaging the two studies, the effect size was +0.13.


*The Center for Research in Educational Policy (CREP) at the University of Memphis examined the efficacy of LLI instruction on struggling readers in districts across the country. The results of the LLI Efficacy Studies revealed that LLI POSITIVELY IMPACTS students’ literacy achievement.

NOTE: The Center for Research in Educational Policy’s report on LLI was evaluated and is recommended by The National Center on Response to Intervention (NCRTI).


*Heinemann, in partnership with third-party, independent researchers, analyzed self-reported district/school data that corroborated the findings of the LLI Efficacy Studies. Read the Data Collection reports here.

Researchers found that LLI students achieved expected reading progress in half the time when compared with typical reading progress.

*2009/2010 Study Key Findings:

  • On average, the total sample of 4,881 LLI students demonstrated reading progress comparable to expected reading progress over eight months during the school year. This progress was achieved during participation in LLI for an average of 17 weeks, or 4.2 months.
  • Post-LLI, 68% of the total sample of 4,881 LLI students demonstrated an instructional reading level at least three levels higher than their pre-LLI level and 12.5% raised their reading skills seven or more levels.
  • On average, the subset of 1,118 LLI students who received LLI as designed demonstrated reading progress comparable to expected progress over an average of almost ten months. This progress was achieved during participation in LLI for an average of 21.1 weeks, or 5.3 months.
  • Post-LLI, 79.2% of the subset of 1,118 LLI students were within two text reading levels of grade-level expectation and 64.8% were at or within one text reading level of grade-level expectation.
  • The 2009-10 study included 824 kindergarten through fifth-grade students with an IEP for Reading or other categories (SPED). With LLI these students made an average of 7.5 months of progress in a little more than 4.5 months.
  • The 2009-10 study included 925 kindergarten through fifth-grade students reported to be English Learners made almost twice the amount of reading progress when compared to typical reading progress over time.


*2010/2011 Study Key Findings:

  • This report analyzed data collected during 2010-2011 school year. Over 2,600 students from 114 schools from 11 states participated. Results show on average a time equivalent gain in reading level of about 9 months after just 4.5 months of LLI.



Teacher Efficacy

Research shows that teachers are the single most important classroom factor in a child’s learning achievement.

*John Hattie’s extensive research:

    • The greatest influence on student progression in learning is having highly expert, inspired and passionate teachers and school leaders working together to maximize the effect of their teaching on all students in their care” (Hattie 2015, p 2).
    • “Collective teacher efficacy” ranked highest on this list of 252 influences on student achievement and is defined as teachers’ belief that they are able to make a difference in student achievement through high expectations.” 

Hattie, J. 2015. What Works Best in Education: The Politics of Collaborative Expertise. London, UK: Pearson

Hattie’s research synthesis showed an effect size of 1.57 on student achievement for collective teacher efficacy, compared to an average effect size of 0.4 for all the interventions and factors he studied. “Collective teacher efficacy” ranked highest on this list of 252 influences on student achievement and is defined as teachers’ belief that they are able to make a difference in student achievement through high expectations. 

*Hattie, J. (2017). Hattie Ranking: 252 Influences and Effect Sizes Related To Student Achievement. (link)


Hattie synthesized 1000 research reviews of 50000 studies. Collective teacher efficacy has a stronger influence on achievement than any other factor.



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LLI System Overview

LLI K-2 Systems (2nd Edition)

LLI 3-5+ Systems


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Learn more about research on the Fountas & Pinnell website