Putting Lexile in Its Place: Addressing Teachers’ Misunderstandings of the Lexile Framework

Three boxes with books in a row, boxes labeled as Easy, Just right, and Too Hard

While text leveling scales, such as Lexile, have been a cornerstone in education for decades (Smith et al., 1989), the adoption of the Common Core State Standards (CCSS; Kendall, 2011) increased the emphasis of text complexity in education immensely. Conversations around text complexity became the focus of CCSS reading professional learning opportunities. While it is important to understand what makes a text complex, over the decade since the CCSS adoption, many educators have unfortunately misconstrued what the purpose of Lexile is, believing that a text leveling scale provides absolute measures and that students should always read texts that are within a “just right” range (Schwanenflugel & Knapp, 2015).

Given that Lexile is ubiquitous, we wondered how educators’ use and perceive Lexile today. In a national survey, we asked 150+ educators about Lexile’s place in education and found that Lexile is used in ways that go beyond the scope of its purpose—often incorrectly. So, we think it is important to put Lexile in its place by addressing its misunderstandings.

The Lexile Framework for Reading

The Lexile Framework for Reading includes over 300,000 books with a Lexile level. Like any text-leveling scale, Lexile focuses on the quantifiable aspects of a text to calculate its difficulty. This means that longer sentences and less frequent words in texts contribute to a higher Lexile score; shorter sentences and more frequent words contribute to a lower Lexile score (Lennon & Burdick, 2004). While Lexile computes a level for a text, it also provides a measure for reader ability.

The strength of Lexile is having a common metric that helps match students to texts (Metametrics, 2017), allowing for better access to materials as texts are matched to students' zone of proximal development (ZPD; Vygotsky, 1978). While matching students to texts is an asset of Lexile, we wondered how educators use Lexile in their practice.

Educators’ Uses and Perceptions of Lexile

In a national survey of 150+ educators, we asked educators how they used and perceived Lexile. Some of their responses revealed a misunderstanding, and subsequent misuse of Lexile, which is cause for concern.

Uses. Given that Lexile’s strength is its ability to match readers and texts, its uses should reflect this strength. While educators in our survey did mention matching students with texts, they also mentioned using Lexile to:

  1. measure students' reading levels and progress at the class, school, or district level,
  2. level texts within a classroom or school library, and
  3. communicate with students, their families, or administrators about students' progress.

The previously outlined uses are consistent with what Metametrics, the creator of the Lexile Framework for Reading, describes as its strengths.

Misusing Lexile as a diagnostic. Other less common Lexile uses by educators demonstrated a misunderstanding of Lexile’s purpose, namely using Lexile as a diagnostic tool. A few educators described Lexile as the “diagnostic tool” that can be used to demonstrate progress and determine learning gaps to better prepare for differentiated instruction. While Lexile can demonstrate progress from one administration to the next, it is not a diagnostic assessment.

When we think about diagnostic assessments in medicine, they are used to confirm or rule out conditions and diseases before the doctor creates a treatment plan. Using Lexile as a diagnostic reading assessment would be like using a thermometer to determine underlying health concerns. A thermometer can tell the medical provider whether or not the patient has a fever, but it cannot tell why. This is exactly what Lexile can do; it provides a number, which can tell us if the reader is within an expected grade-level range or if there is cause for concern and deeper probing through a diagnostic reading assessment is required.

Perceptions. Although a lot changed during the time of the COVID pandemic, teachers’ perceptions of the importance of Lexile measures did not change. When we asked educators about the importance of Lexile before and after the pandemic, nearly ¾ of educators said that its importance did not change because of the pandemic. One educator mentioned that Lexile is a “measurement on which a child’s reading level is measured,” so she was not sure why it would be different. Other teachers suggested that Lexile is only slightly important since they have other tools that focus on measuring students’ reading skills that are standards-based and go beyond providing a singular reading level.

10.2% I don't know, 5.1% Not at all important, 9.6% Slightly important, 25.5% important, 26.8% fairly important, 22.9% very important

Satisfaction. When asked about their satisfaction with Lexile, over half of respondents said they were at least somewhat satisfied with Lexile. Educators who said they were satisfied mentioned the use of Lexile to match students with texts as a reason for their satisfaction. One teacher mentioned that she was able to find the “right” texts for her students to read. Conversely, some of the educators who said they were dissatisfied with Lexile shared the sentiment that Lexile does not give them enough information to support students. In some ways, it is like taking an individual’s temperature, finding out the individual has a fever, and not knowing what to do about the fever.

8.2% - I don't know, 5.3% - Very dissatisfied, 8.8% - Somewhat dissatisfied, 21.4% - Neither dissatisfied nor satisfied, 40.3% Somewhat satisfied, 15.1% very satisfied

Confidence. What is interesting is that over 30% of the respondents reported a lack of confidence in how to use Lexile, which suggests that professional development in the use of Lexile is needed. One respondent who said she was completely confident in interpreting results, reported that she cautiously uses interpretations of students’ results because of the storied history of readability formulas. She suggested that Lexile provides insight, but not an absolute truth of what a student can do or what they require instructionally. Her suggestion supports the need for additional reading measures that illuminate students’ strengths and areas of need.

8.2% Not at all confident, 6.3% slightly confident, 17.6 somewhat confident, 44% fairly confident, 23.9% completely confident

Misplaced expectations. The most common theme to emerge from respondents’ open-ended responses relates to mixed feelings about Lexile. It seems teachers recognize the power of using Lexile to match students to books, but feel like the instructional implications are unclear. However, the sentiment is a result of a misunderstanding of what Lexile is and, consequently, misplaced expectations. By design, Lexile is intended to match students to books, not diagnose reading difficulties. A novice teacher’s story about her use of Lexile illuminates the danger of misunderstanding an assessment’s purpose.

As a first year teacher, the educator looked for measures that would help her identify what her middle school students needed to become skilled readers. When her school’s literacy specialist talked about Lexile, the teacher thought that she had found the “magic ticket.” She administered the assessment and then spent time looking for and buying books for her classroom library that matched students’ Lexile levels and interests. She helped students find high interest books at their Lexile level throughout the school year. Then, to her dismay, students did not improve their reading skills, and quantitative measures provided by Lexile remained stagnant from administration to administration.

The teacher believed that much like Goldilocks, the “just right” book, would set students up for success. In hindsight, she realized that what she did not take into consideration was that Lexile is a measure that provides a number representing how well a reader comprehends a text based on text leveling, specifically, word frequency and sentence length. In conversations with more experienced teachers, she recognized the need for explicit instruction in reading skills and processes to better meet students’ needs. She also realized that students need to increase the complexity of texts they read throughout the school year as compared to reading within their “comfort” zone.

The Power of Lexile

Lexile can help mitigate learning loss by matching students and instructional materials at appropriate levels. One teacher shared that to overcome post-COVID lockdowns and subsequent learning loss, her school used Lexile measures to plan instruction based on students’ reading levels. By taking students’ reading levels into consideration, teachers at her school were able to find appropriate texts, in students' ZPD, aligned to curricular goals. Then, over the course of the school year, they included more complex texts that gained in complexity until meeting grade level expectations by the end of the year. Teachers using Lexile measures in this way, allowed students to strengthen their reading skills with easier texts before being placed into more difficult texts. This teacher also used a diagnostic reading assessment in tandem with Lexile to better understand what students were able to do and what skills students required additional support.

The real power of Lexile comes when it is partnered with a diagnostic assessment. By partnering Lexile with a diagnostic reading assessment, educators receive a more holistic picture of what a reader can do and the areas where the reader requires support. Then, the teacher can use the Lexile measure to match the student to appropriately leveled texts during instruction. The combination of Lexile with a diagnostic reading assessment strengthens the data teachers receive to create instructional plans that improve reading outcomes.

Many reading assessments now include Lexile (see the list) to provide a starting point for text complexity to better meet curricular goals; however, most of these are not diagnostics, but benchmarks. Recently, Metametrics and Capti partnered to offer a Lexile measure as part of Capti Assess with ETS ReadBasix. Including Lexile on a diagnostic reading assessment allows teachers to receive necessary data to better meet students’ reading needs, thus creating a place for Lexile that supports curricular goals through its intended purpose: matching readers with texts.

For more on how to use Lexile, see our guide on Harnessing the Power of Lexile.

We look forward to more conversations about the Science of Reading and how to best support reading comprehension. If you have a question about the Science of Reading or would like us to consider a specific topic, let us know here.

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This and many other topics related to the Science of Reading are covered by the Professional Development training that is offered for the ETS ReadBasix assessment.


  • Kendall, J. S. (2011). Understanding common core state standards. ASCD.
  • Lennon, C., & Burdick, H. (2004). The Lexile framework as an approach for reading measurement and success. [White paper]. The Lexile Framework for Reading. https://cdn.lexile.com/m/resources/materials/Lennon__Burdick_2004.pdf
  • Metametrics (2017). Lexile measures and grade levels. https://lexile.com/wp-content/uploads/2017/08/T1.4.FAQ_LM-and-Grade-Levels.pdf
  • Schwanenflugel, P. J., & Knapp, N. F. (2015). The psychology of reading: Theory and applications. Guilford Publications.
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