Vocabulary Matters: Addressing the Reading Crisis in Grades 4-8

For years, early elementary school classrooms have been on the front line of the movement to improve reading ability. Yet according to The Nation’s Report Card, after more than a decade of phonics reform, approximately 70% of public school students in grades four and eight performed below the NAEP Proficient level in reading.

Around fourth grade, curriculum begins to shift emphasis from teaching reading through decoding to using reading as a tool for learning. Students haven’t forgotten how to sound out words—they simply don’t know how to tackle complex spelling patterns, syllable structures, Greek and Latin roots, prefixes, and suffixes.

In short, explicit decoding instruction often decreases after 3rd grade, right before students encounter unique vowel teams, foreign roots, and all the other idiosyncrasies that define the English language. While teaching advanced phonics and morphology is a piece of the equation, an often overlooked critical skill is vocabulary acquisition.   

The Missing Half of the Reading Crisis

For years, reading reform focused on improving decoding. But decoding is only part of the equation. As texts become more complex, students must also draw on increasingly sophisticated vocabulary, background knowledge, language comprehension, and fluency. 

Starting in grade four, students are increasingly expected to use reading to learn new content and stop “learning to read” (Chall and Jacobs, 2003). After grade three, vocabulary demands increase dramatically. Instead, their lessons shift to “reading to learn.” But even for students with a strong decoding foundation, knowing enough words to understand more complex texts is a challenge. That’s where vocabulary comes in. Vocabulary knowledge is strongly associated with reading comprehension and contributes to academic achievement (Lawrence et al., 2019; Bleses et al., 2016). And in middle and high school, students must learn tens of thousands of words simply to access grade-level content. The challenge, however, is that vocabulary development has not received the focus it deserves. 

We’ve Made Strides in Phonics. We Forgot Vocabulary.

Vocabulary is one of the five core building blocks of the science of reading, alongside phonemic awareness, phonics, fluency, and comprehension. But it’s received a fraction of the attention decoding has. 

States across the country have invested heavily in the implementation of the science of reading, with many adopting evidence-based curricula, teacher training, and early literacy policies. These efforts are helping to reshape reading instruction, particularly in grades K–3. But improving literacy outcomes requires sustained attention well beyond the foundational years. After all, reading development doesn’t stop after students learn to decode.

While many associate the science of reading with phonics and foundational skills, those competencies are only the beginning of literacy development. After approximately third grade (around 600L on the Lexile scale), students transition from primarily learning to read to reading to learn. From that point forward, vocabulary, knowledge-building, sentence complexity, disciplinary literacy, and reading stamina become increasingly important.

Despite its importance, however, vocabulary has fallen out of focus. As digital and short-form content have become more prevalent, reading habits have increasingly shifted away from whole books (Baron and Mangen, 2021). Less time spent with sustained, long-form reading may mean fewer opportunities for students to encounter the diverse and sophisticated vocabulary that books can provide (Montag, Jones, and Smith, 2015). Further, without a focus on sustained reading, students lack the stamina and vocabulary needed to tackle increasingly complex texts.

How Lexile Tools Promote Vocabulary Development

Helping educators and students identify high-value words in a text is a key step towards vocabulary development. Using Lexile vocabulary tools, publishers and curriculum providers can strengthen alignment with the science of reading in the instructional materials they are developing by identifying high-frequency phrases, academic and domain-specific word lists, and book-specific vocabulary. 

For example, Lexile® PowerV identifies which words have the most value for instruction based on three criteria:

• Difficulty: PowerV pinpoints more challenging words in a text and automatically identifies words that are 50L to 250L above the Lexile measure of the content under development. 
• Relevance: Using PowerV, publishers and curriculum providers can identify words that appear more frequently in the text. The more frequently a word appears, the stronger the relationship it has with the specific text.
• Consequence: PowerV helps content creators determine the words students need to know for success at school by aggregating key vocabulary by level from academic word lists developed by linguistic and education experts.

From Decoding to Understanding

When students have strong vocabulary, they can access complex texts, express nuanced ideas, and keep pace as academic subjects become more demanding. Students who build strong vocabulary during late elementary and middle school years carry that advantage into high school, while those who don’t often fall behind. 

Vocabulary development also has implications far beyond the classroom. As students move toward college and careers, they are increasingly expected to understand specialized language, technical terms, instructions, policies, and other complex texts. In the workplace, strong reading skills help employees interpret information, solve problems, and make informed decisions—and vocabulary is essential to that understanding.

Building vocabulary in the middle grades, then, isn’t simply about helping students comprehend today’s assignments. It’s part of preparing them to navigate the increasingly specialized language they will encounter in high school, postsecondary education, and the workplace.

Using Lexile vocabulary tools, publishers and curriculum providers can ensure the rich texts they develop support strong vocabulary development by identifying challenging words that are 50L to 250L above the Lexile measure of the content they’re developing, identifying which words appear more frequently within the texts, and aggregating key vocabulary from academic word lists. As a result, teachers can make vocabulary instruction more intentional and engaging, helping students build the language they need not only to comprehend increasingly complex texts, but to succeed in high school, postsecondary learning, and the workplace. 

Sources:

• Baron, Naomi S., and Anne Mangen. “Doing the Reading: The Decline of Long Long-Form Reading in Higher Education.” Poetics Today 42, no. 2 (2021): 253–279. 

• Bleses, D., Makransky, G., Dale, P. S., Højen, A., and Ari, B. A. “Early Productive Vocabulary Predicts Academic Achievement 10 Years Later.” Applied Psycholinguistics, 2016.

• Chall, Jeanne S., and Vicki A. Jacobs. “The Classic Study on Poor Children’s Fourth-Grade Slump.” American Educator, Spring 2003. 
• Lawrence, J. F., Hagen, A. M., Hwang, J. K., Lin, G., and Lervåg, A. “Academic Vocabulary and Reading Comprehension: Exploring the Relationships Across Measures of Vocabulary Knowledge.” Reading and Writing, February 2019. 
• Montag, Jessica L., Michael N. Jones, and Linda B. Smith. “The Words Children Hear: Picture Books and the Statistics for Language Learning.” Psychological Science 26, no. 9 (2015): 1489–1496.