Lexile® Framework for Reading

The Lexile Framework for Reading is a scientific approach for measuring both reading ability and text complexity. Reading ability is conceptualized as a latent trait that influences a reader’s chance of success in comprehending professionally edited text, and text complexity is a quantitative feature that represents the difficulty of a text.

The Lexile Framework for Reading - By the numbers

About Lexile Measures, Fact Sheets, Guides, Lexile Maps, and El Sistema Lexile Para Leer Explainers

Lexile Educator Guide

Lexile Librarian Guide

Lexile Parent Guide

Managing Multiple Measures Resource Center

Understanding Primary & Secondary Resources


What is the Lexile Framework for Reading?

The Lexile Framework for Reading is a scientific approach to understanding the reading relationship between text and learner. The Lexile scale can be used to measure both the complexity of a text and the reading ability of a learner. A Lexile learner or student measure represents a person’s reading ability on the Lexile scale. A Lexile text measure represents a text’s difficulty level on the Lexile scale. When used together, they can help a reader choose a book or other reading material that is at an appropriate difficulty level. The Lexile student measure can also be used to monitor a reader’s growth in reading ability over time and connect them to reading demands of the real world.

How are the Lexile and Quantile Frameworks similar and different from each other?

The Lexile Framework for Reading and the Quantile Framework for Mathematics are both academic measurement systems that make the measurement of student performance and the measurement of material complexity on a single scale possible. Both are based on empirical (observed) relationships between learners and materials. The scales and their units accurately describe measures from beginner to advanced. The scales are independent, meaning that student and material measures can be produced from many assessments and for reading and math materials from many sources. They differ with respect to the academic skill and material measured. On the learner or student side, the Lexile Framework for Reading measures a learner's reading ability, or overall reading comprehension, and the Quantile Framework measures a learner's ready to learn level, the difficulty of level for math skills and concepts. On the materials side, the Lexile Framework measures the complexity of prose text based on quantifiable text features while the Quantile Framework measures the complexity of math skills and concepts based on the mathematical relationships between each skill and concept.

What is a Lexile text measure?

The Lexile text measure describes complexity based on features of prose text. Years of research indicates that two of the most powerfully predictive indicators of text complexity are sentence length and vocabulary (though not the only indicators). By measuring those features, MetaMetrics is able to place a piece of text, or book, on the Lexile scale. There is also a Lexile measure that communicates a learner's ability level on the same scale.

What is the Lexile Analyzer?

MetaMetrics® analyzes texts using Lexile Analyzer software that evaluates predictive dimensions of the text that have been shown to impact comprehension and produces metrics via the proprietary Lexile algorithm. The outcome is the text complexity, expressed as a Lexile measure, along with information on the word count, mean sentence length and mean log frequency. Texts below 650L receive additional information specific to the needs of early learners.

How does a student receive a Lexile measure?

Learners receive a Lexile measure by taking a Lexile-enabled assessment.

Is there a single assessment that reports Lexile measures?

No, the Lexile metric is instrument independent. This means that almost any standardized test could report reading scores along the Lexile scale after undergoing the MetaMetrics in-house linking process.

What are the letters in front of the Lexile measure? What are Lexile codes?

When a book is written for a specific use or style that may be of interest to end users, MetaMetrics provides codes to accompany the Lexile measure. ‘BR’ is placed with Beginning Reading material, ‘AD’ indicates Adult Directed books written for adults to read aloud , ‘HL’ denotes books of High interest but Low complexity, ‘IG’ indicates Illustrated Guides, and ‘GN’ is used for Graphic Novels.

Read more here.

What does a Lexile measure on a text mean?

A Lexile measure is a scientific, quantitative way to precisely express text difficulty. A Lexile measure informs the reader of the complexity of reading material based on characteristics from the text that influence comprehension. So, readers can easily ascertain whether a text is suitable for them, either as a text at their level, a challenging text or an easy read. Teachers and parents may also use the information to help support the learner to find the best books to match their reading ability and to ensure progress.

What does a text’s Lexile measure not do?

The Lexile measure offers publishers, educators, parents, and learners an idea of the text complexity they can expect from a particular book or passage. As a quantitative measure of difficulty it is a valuable tool but cannot replace teacher and parent judgement on subjective features like age-appropriateness. A Lexile measure is simply a measure of text complexity and should be considered one piece of information used to guide decisions about whether a learner will be able to comprehend a particular piece of text. When it comes to grading content, age-appropriateness, levels of scaffolding and illustrative support, or making reader-task decisions, publishers, educators, and parents are the best resource for learners.

What does a learner’s Lexile measure mean?

A learner’s reported Lexile measure represents the complexity level of a text where a learner is forecast to have 75 percent comprehension with independent reading. Reading at this level is challenging so as to promote growth but not so difficult that the student is overly frustrated.

What are Lexile measures and the Lexile scale?

Lexile measures are the numeric representation of an individual’s reading ability or a text’s complexity followed by an “L” (for Lexile). The Lexile Framework for Reading is based on the Lexile scale—a common scale for measuring an individual’s reading ability and texts. The scale reaches below 0L for beginning reading texts and learners to over 1600L for advanced texts and learners.

What are Beginning Reading (BR) measures?

BR stands for Beginning Reading, and it indicates a Lexile measure for a text or student that occurs below 0L on the Lexile scale. Beginning Reading measures follow this format: BR###. The smaller the number following the letters BR, the more advanced the reader is. For example, a student with a Lexile measure of BR100L is a more advanced reader than a student with a Lexile measure of BR300L. Once a Lexile measure crosses above 0L, then the smaller the number, the less advanced the reader or less complex the text. For example, a book with a Lexile measure of 100L is less complex than a book with a Lexile measure of 300L.

How is Lexile Framework for Reading different from other reading complexity systems?

There are lots of ways to measure a text. In fact, readability formulas have been around for well over a hundred years. What makes the Lexile Framework for Reading unique is that it measures both the reading material and the learner’s ability. The technical way of describing the Framework is as a ‘conjoint measurement model’, which is just a technical way of saying the Lexile scale can be used to measure the difficulty of a book and the reading level of a learner. Because the Lexile Framework for Reading measures both text complexity and learner ability on a single scale, educators can match texts to students for targeted practice, progress monitoring, and projecting expected growth easier.

How does sentence length impact complexity?

Sentence length is a powerful indicator of the syntactic complexity. Longer sentences typically contain more clauses, thus, more information. Learners that read a long sentence must retain information for an extended period before they arrive at the complete message. The learner’s short-term memory is working to hold and then process all the information. Shorter sentences put less burden on short-term memory.

How does the Lexile Framework for Reading connect to the real world?

A benefit of using the Lexile Framework for Reading is that it opens up new possibilities to users. Lexile metrics are employed throughout the world in high stakes assessments, learning technology platforms, and published works. Our research encourages success by illuminating the reading ability necessary to succeed in college, university, and individual careers. Because the Lexile scale can be applied to any sort of prose text, many organisations, institutions, educators and Departments of Education have used the Lexile scale to measure real-world materials: workplace materials, assessments, primary and secondary textbooks, entrance examinations, and even university textbooks. Having that information allows educators to compare a student’s status to the demands of real-world reading, making goal attainment easier.

Does the Lexile Framework assess fiction and non-fiction texts in the same way?

Yes, there is only one Lexile Framework for Reading. It is developed to evaluate all prose in the same manner. The features of the text impact the overall complexity.

What is the relationship between a learner’s Lexile measure and targeted reading?

Learners that read books at their reported Lexile measure can expect an estimated 75 percent comprehension rate. This 75 percent comprehension rate is called “targeted” reading. This rate is based on independent reading. If the reader receives assistance, the comprehension rate will increase. Reading books that measure 100L below and 50L above the learner’s Lexile measure is considered the optimal reading range for reading growth. Texts in this range should present just enough challenge to facilitate reading growth, but not so much challenge that they lead to frustration. For example, if a reader has a Lexile measure of 1000L, he will be forecasted to comprehend approximately 75 percent of a book with the same Lexile measure (1000L).

Why would a learner’s Lexile measure change?

A learner’s Lexile measure can change for a few reasons. The most common reason for change, and the most welcomed, is due to growth in a learner’s reading ability. A change in Lexile measure could also be due to assessment through different instruments that both report Lexile measures. To illustrate, imagine purchasing two thermometers from different manufacturers and then using them to take the temperature of a pot of hot water. Even though both report temperature on the same scale differences in calibration impact the reported measure just as two different tests that report Lexile measures may result in slightly different measures. The final reason for changing measures is something called “measurement error”. This does not mean a scoring mistake but rather any number of internal or external influences on the reported reading ability measure. Usually, standardized tests are given in uniform, controlled environments to minimize the influence of external factors. Internal factors, like hunger, anxiety and mistakes are more difficult to control. Ultimately it is up to students, parents and teachers to reflect on the scores in the context of broader knowledge about the learner. Whenever a score is inconsistent with other information, then it should be viewed cautiously. Often, a thoughtful inquiry will provide insight into the learner’s performance.

What kinds of text can receive a Lexile measure?

Lexile measures assess the complexity of prose text. Not all texts are appropriate for analysis. Texts such as lists, recipes, poetry, and song lyrics are not analyzed because they lack conventional punctuation. Standard prose, informational or literary, is appropriate for analysis.

How can I find the right Lexile range?

A Lexile reading range spans 50L above to 100L below a learner’s Lexile measure. For example, a 500L learner can stretch their ability by selecting books from 400L to 550L based on their 75 percent comprehension rate measure. That same reader may select easier independent reading material set on a forecasted 90 percent comprehension rate between 150L to 300L.

Can literary genre impact a book’s Lexile measure?

A book’s genre is not considered when receiving its Lexile measure. However, features of a text do influence complexity. The following examples highlight how style can impact complexity. Stream-of-thought or journal style books may include longer than average sentences which challenge readers’ short term memory and drive the Lexile measure upward. A non-fiction text written for the purpose of instruction may employ shorter sentences with a repeated structure, which lowers the Lexile measure, in order to aid a learner’s retention of a particular subject or concept.

Do Early Reading Indicators apply to students?

Early Reading Indicators do not describe any characteristics of a student. Early Reading Indicators only describe the characteristics of the text. The information can be used to select reading material that is appropriate for students with specific reading needs. For example, a text with low decoding demands/low decoding indicator (i.e. many easy-to-decode words) could be selected for a student who needs practice reading easily decoded words.

How are Lexile measures reported on materials?

Lexile measures are reported digitally, in a catalog, or on a book’s cover. A Lexile measure is a number followed by the letter “L.” Lexile measures range from below 0L for beginning texts to over 1600L for advanced texts. A higher number indicates more challenging text or greater ability learner than a lower number.

How can the Lexile forecasted comprehension rate be adjusted?

The Lexile Framework for Reading is a developmental scale that can be adapted for individual needs; the forecasted comprehension rate can be adjusted to target reading practice for different needs. The reported 75 percent targeted comprehension rate is a comfortable place for most learners. There they will be challenged to promote growth. Adjustments can be made up and down to suit individual’s needs. If a book’s measure is higher than the reader measure, forecasted comprehension goes down. If the text measure is lower than the reader measure, forecasted comprehension goes up. One can select books for easy independent reading by adjusting upward to 90 percent or higher forecasted comprehension by selecting a book with a Lexile measure approximately 250L below the reader’s measure. For example, a reader with a measure of 900L would choose a book with a measure around 650L.

How does word choice impact complexity?

Vocabulary choice is an important indicator of the complexity of a text. Familiar or frequently used words are less challenging to a learner than rare or less frequently used words.

How does the Lexile scale help explain proficiency standards?

While there is judgment in labeling the weather cold or hot at 70° Fahrenheit, exceeding the maximum speed, or being tall enough to ride a certain ride, in each of these examples the measurement scale or metric allows for comparability. Driving 80 mph in North Carolina is the same as driving 80 mph in Montana, but the behavior has different labels and consequences. Just as we have comparability in the measurement scales in these examples, we have this same comparability in the realm of educational assessments that report Lexile measures. The good news is that students reading at 725L on any assessment are reading at the same level.

In the same way, states and assessment publishers have decided what scores describe proficient reading performance. Each state department of education or assessment publisher has their own definition of what it means to be “proficient” and uses that definition to define a particular range of scores to represent proficient performance. For example:
  • On a state English Language Arts/Reading Test (Grade 3), the Sufficient range is from 439 to 441 (725L to 790L) and the Proficient range is from 442 to 451 (795L to 1025L).
  • On one interim/benchmark assessment, the Proficient range is from 520L to 820L.
  • On another interim/benchmark assessment, students reading at an appropriate level at the end of Grade 3 should be reading between 3.7 and 3.9 (495L to 537L).

Despite these different proficient standards, the underlying scale to measure a child’s reading ability does not change. Today, about twenty states provide Lexile measures as a part of reporting the state assessment results. And in each of these states, districts are using at least one of the dozens of interim and benchmark assessments that also report Lexile measures. Thus, by using a common scale such as the Lexile scale, we are providing more clarity and comparability in the measurement of reading.