Thursday, April 11, 2013

Lexiles & Readability

A LOOK AT LEXILES and Text Complexity

While delivering PD yesterday,  a teacher asked me, "What's a Lexile?"   I wanted to say, "where have you been?"  But the reality is--I commend her for not being afraid to ask what we think is such a basic question.  We forget that some people have been so busy working in the trenches that they haven't been able to keep up. (They've been too busy administering tests, Student Learning Objective assessments, state exams and more.) So, listed below are the basics of LEXILES 101. 

Essential understandings: 

  • The Common Core has defined where "college and career ready" (CCR) students should be reading and it's a 1450  Lexile.  Therefore, they scaffolded in reverse levels to graduate students at the appropriate level.  These Lexile levels are more difficult than where typical students are reading.
  • Lexile is an algorithm. It is a mathematical assessment of a linguistic product. 
  • Lexiles (and other readability statistics) are fallible. (For instance, it is not valid for prose or drama and is less valid for fiction in 1000+ Lexile range.) 
  • The parent organization to the CCSS, (CCSSO formally called the Governor’s convention) recently released a white paper verifying the validity of text complexity. Therefore, we have to pay attention to this essential shift to embrace "rigor" in reading.
  • To read the recent white paper from the Council of Chief State School Officers click here. This article compares a number of algorithms and the summarizes text complexity for the CCSS. 
  • Text complexity formulas were meant for instructional purposes.
  • Pleasure reading should be allowed at any level and this is validated in the Common Core, Appendix A, page 9, paragraph 1:

 It is very interesting, to compare the variables used among the six different "approved" complexity measures. Metametrics (Lexile) uses the simplest measure of only word count and sentence length. ( provides a search tool for books, but many are missing.)  Other companies including Accelerated Reader (ATOS) and Pearson, DRP, etc... add additional measures of review such as punctuation, a 100,000-word vocabulary match, and more. Therefore, we would conclude that the ratings of the latter companies would be more accurate picture of complexity and appropriateness. This quote from page 17 of the white paper puts it diplomatically:

"There is no clear "gold standard" measure of text difficulty against which to compare the various metrics. Instead, we compared each metric against various reference measures based on grade level and student comprehension data for five sets of passages gathered for the study. These are defined and discussed in the sections following. Although there are limitations in the validity of these indicators as measures of text difficulty, the variety in their construction allows us to observe the robustness of the metrics and consider how different reference measures might affect their performance."

Be sure to note that Microsoft Word's Flesch-Kincaid measure has also been proven valid. This picture shows how to "turn on" readability statistics within Word:   

Readability statistics, is only one characteristic to examine for instructional materials.  Please see the charts below to identify correct grade levels and Lexiles - or level of complexity.

The Common Core has asked teachers to evaluate classroom materials for quality as well as quantity.  Complexity is only one piece of the puzzle. In addition, a teacher, librarian, or educator, has to pay attention to:

Complexity - Lexile, vocabulary
Qualitative measures -value
Reader and the task -is there enough in the text to foster good discussion, value -added assignments, and begin a knowledge exploration. How can I use this novel or passage to foster critical thinking skills?

Every reading program (F and P, AR, Reading Counts, etc.) uses as its baseline, some metric to measure difficulty or "readability".

Here is a chart by Perma-bound, which correlates the different reading measures:


  1. This type of door is made from two sheets of galvanized steel up to 0.8 mm thick with a core of honeycomb paper. This type of fire door resists smoke and high temperature of fire has been tested according to standard, withstanding time is 1 hour.
    See more at the link: Cua thep chong chay | Cua chong chay