In this post, Understanding Text Complexity—Quantitative Measures, we will continue discussing another measure of text complexity that teachers should use when selecting texts for classroom use.
Quantitative factors refer to things about the text that can be counted or “quantified.” These include factors such as word length and frequency, sentence length, and the complexity of the vocabulary used in the text.
We want students to read text that could be called “Goldilocks text”—not too easy but not too hard either. To match students with “just right” text that challenges them but does not overwhelm them, it is important to examine the levels of complexity contained in the text.
What are Quantitative Measures of Text Complexity?
Publishers generally rely on quantitative measures to determine a text’s difficulty. Computer software often calculates a text’s “readability”, considering factors such as word length, word frequency, sentence length, and text cohesion.
There are many formulas, such as the Flesch Reading Ease Formula, the Flesch-Kincaid Index, Fry’s Readability Graph, the Dale-Chall Readability Formula, the Spache Readability Formula, and the Lexile Framework for Reading.
A readability measure can only give us a sense of the difficulty of the text’s construction. It cannot tell us whether the subject matter is appropriate for the reader or whether the reader has the background knowledge required to comprehend the author’s message.
Using Readability Formulas to Assess Text Complexity
Let’s examine how understanding the Lexile level of texts might help us in the classroom. A book with a Lexile level of 1200 would be more of a book used in high school, while a book with a Lexile level of 800 might be more appropriate for a student in grades 4 or 5.
At the lowest grade in each band, students focus on reading texts within that text complexity band. To reach the higher bands, students must “stretch” their skills to read a certain proportion of texts that belong to the next higher text complexity band. This pattern repeats itself as students progress to higher grade levels.
This allows students to build on earlier literacy gains and challenge themselves by reading texts at higher complexity levels. Lexile measures and ranges help to determine what text is appropriate for each grade band and suggest what should be considered “stretch” text.
This does not mean that if a student cannot read texts written in the “stretch” Lexile band, we push them into text that is too difficult for them. Instead, we scaffold and guide our students to help them stretch and grow their reading skills and close the gap between their current reading level and where we want them to be.
As students move through the grades, they apply their skills to increasingly complex texts.
Here are the suggested grade-level “stretch” bands we strive to help our readers reach.
| Text Complexity Grade Band | Previous Lexile Bands | Current “Stretch” Lexile Reading Target Bands |
| K-1 | N/A | N/A |
| 2-3 | 450-725 | 450-790 |
| 4-5 | 645-845 | 770-980 |
| 6-8 | 860-1010 | 955-1155 |
| 9-10 | 960-1115 | 1080-1305 |
| 11-12 | 1070-1220 | 1215-1355 |
While a readability level can help match readers with appropriate texts, it is only one measure of text complexity. Qualitative measures and reader and task measures must also be considered.
When selecting a text, you want it to be able to stretch your students but not overwhelm them. This is the secret to finding a “just right” text.
Learn more about how to match readers to text and deepen comprehension in my book: Literacy Strategies for Grades 4-12: Reinforcing the Threads of Reading.
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Learn more about matching readers to the tasks we want them to do,
Learn more about the Qualitative Measures of Text Complexity.
