What Do Lexiles Measure?
Lexile scores are used to match reader ability with text difficulty. Regardless if students are enrolled in Read 180, a program dependent on Lexile measurements, these scores can prove useful to all teachers when selecting appropriate reading materials for their courses, as well as guiding students in being successful independent readers.
Resulting from over 20 years of on-going research, Lexile measures predict a range of comprehension difficulty based on semantic (word frequency) and syntactic (sentence length) complexity. Longer sentence lengths and words of lower frequency lead to higher Lexile measures, while shorter sentence lengths and words of higher frequency lead to lower Lexile measures. Lexile scores range from 200L for beginning-reader materials to above 1700L for advanced text. When students take a standardized test, such as the Scholastic Reading Inventory, they receive a Lexile score that can then guide teachers to match students with texts that are appropriately challenging—texts that are in students’ zones of proximal development.
It’s important to note that a Lexile measure does not have a direct correlation to a grade-level equivalent. (See chart below). Instead, it predicts a range of readability levels, extending 50L above and 100L below a student’s score. Plus, each score is subject to a standard error of measurement, further increasing or decreasing the predicted range by as many as 153L. For example, a1000L score—not counting its standard error of measurement--would predict a reading range of 900L to 1050L for that student, with a text measuring above 1050L proving too difficult for the reader to construct meaning. Likewise, a10th-grade textbook measuring 1200L will not be appropriate for all reading levels represented in a heterogeneous class. Knowing students’ Lexile scores, however, can guide teachers in selecting reading materials and making accommodations by providing appropriate materials, so that all learners can be engaged in the learning process.
Grade / Below Basic / Basic / Proficient / Advanced7 / 549 & Below / 550 – 849 / 850 – 1100 / 1101 & Above
8 / 599 & Below / 600 – 899 / 900 – 1150 / 1151 & Above
9 / 649 & Below / 650 – 999 / 1000 – 1200 / 1201 & Above
10 / 699 & Below / 700 – 1024 / 1025 – 1250 / 1251 & Above
11 / 799 & Below / 800 – 1049 / 1050 – 1300 / 1301 & Above
Another very important consideration is recognizing what a Lexile does not measure. For example, you might be surprised to learn that The Grapes of Wrath, by John Steinbeck, has a 680L, while Hatchet, by Gary Paulsen, scores a 1020L. Other factors not measured that add to the difficulty level with literary works are such characteristics as inferential passages, multiple points of view, flashbacks, and symbolism, as well as the background knowledge and interest in the content that students bring—or don’t bring—to the reading. Similarly, text features frequently found in textbooks, such as graphs, illustrations, and maps, are not figured into a Lexile score.
As a result, when selecting appropriate reading materials, the Lexile score is merely one factor to consider. Still, Lexile measurements are a starting place. For more information, including databases and tools for determining Lexile scores, go to www.lexile.com.
Lexile Levels
On Grade Level Lexile Range
Grade 1 / Grade 2 / Grade 3 / Grade 4 / Grade 5 / Grade 6 / Grade 7 / Grade 8 / Grade 9 / Grade10 / Grade11100-
400 / 300-
600 / 500-
800 / 600-
900 / 700-
1000 / 800-
1050 / 850-
1100 / 900- 1150 / 1000- 1200 / 1025- 1250 / 1050-1300
Grade / Below Basic / Basic / Proficient / Advanced
1 / --- / 99 & Below / 100 – 400 / 400 & Above
2 / 99 & Below / 100 – 299 / 300 – 600 / 601 & Above
3 / 249 & Below / 250 – 499 / 500 – 800 / 801 & Above
4 / 349 & Below / 350 – 599 / 600 – 900 / 901 & Above
5 / 449 & Below / 450 – 699 / 700 – 1000 / 1001 & Above
6 / 499 & Below / 500 – 799 / 800 – 1050 / 1051 & Above
7 / 549 & Below / 550 – 849 / 850 – 1100 / 1101 & Above
8 / 599 & Below / 600 – 899 / 900 – 1150 / 1151 & Above
9 / 649 & Below / 650 – 999 / 1000 – 1200 / 1201 & Above
10 / 699 & Below / 700 – 1024 / 1025 – 1250 / 1251 & Above
11 / 799 & Below / 800 – 1049 / 1050 – 1300 / 1301 & Above
Yearly Lexile Growth Expectation
Current Lexile Range / One Year’s Growth in Lexiles / Two Years’ Growth in Lexiles0-281 / 198 / 385
282-519 / 174 / 335
520-696 / 123 / 288
697-786 / 82 / 139
787-875 / 49 / 154
876-1034 / 36 / 185
1035-1237 / 39 / 184
1238-1255 / 26 / 69
1256 + / 46 / 92