Why we don’t offer Lexile level adjustments in our science lessons – and what we do instead

Reading is a core part of learning science – but for many students, it’s also one of the biggest hurdles. The language of science can be dense, technical, and unfamiliar, especially for struggling readers and English language learners. As educators, we’ve all seen students disengage – not because they couldn’t understand the science, but because the reading got in the way.

So it’s no surprise we’re often asked:

 “Why doesn’t Stile offer Lexile level adjustments or simplified versions of science texts?”

It’s a great question – and one we’ve explored in depth.

The short answer?

Simplifying science texts doesn’t always lead to better learning. In fact, it can sometimes do more harm than good. 

The most effective approach is to support students with evidence-based literacy scaffolds and to explicitly teach them the strategies they need to confidently engage with complex texts. As a science company, we’re committed to ensuring that anything we implement is both research-backed and instructionally robust, and as such, we’ve approached supporting students to access grade-level texts using an evidence-informed approach.

A plot twist you might not expect: What the research says

Several studies have explored whether simplifying texts improves comprehension – and the results are inconsistent at best. In many cases, simpler texts do not lead to better outcomes. Here's a quick summary of key findings:

• Struggling readers often gain no extra advantage from “easy” versions of texts compared to grade-level texts – and may even make greater progress with more challenging texts under guided instruction. (O’Connor, Swanson & Geraghty, 2010)
• Only students reading far below grade level benefit from simplified texts; most others do just as well with complex texts when instructional support is provided.(Lupo et al., 2019)
• A meta-analysis of 45 studies involving 6,477 learners found only a small overall benefit to simplifying STEM texts – mostly for students with low content knowledge. Clarifying or elaborating content helped, but simply shortening sentences or replacing complex words did not yield significant gains. (Strohmaier, Ehmke, Härtig & Leiss, 2023)
• Teaching text-structure strategies, rather than lowering the text level, enabled 7th graders to comprehend science material just as well as when texts were simplified. (Wijekumar, Meyer & Lei, 2017)
• Decades of simplifying school textbooks have been linked to declines in vocabulary development and reading achievement. (Hayes, Wolfer & Wolfe, 1996)
• Scientific terminology is the key offender when it comes to lexile level, but these terms are core to learning the content in the unit. You can't substitute them away. Unlike general complex words, science terms can't just be replaced with simpler ones without losing meaning. So, while they raise the Lexile level and challenge comprehension, they must be taught explicitly rather than removed or simplified. (Snow, 2010)

Compare these two examples below:

Our team tried to lower the Lexile level of a text, but it was challenging to reach the target grade level without removing key scientific terms. Even after simplifying the surrounding text, the overall complexity remained high because the technical vocabulary raised the Lexile score. The version on the right shows the best possible outcome under these constraints.

Want to explore more? Literacy expert Timothy Shanahan offers a useful overview in this article: Should We Teach Students at Their Reading Levels?

In short: making texts easier doesn’t guarantee better understanding. For most students, it’s not the complexity of the text that’s the problem – it’s whether they’ve been taught how to access it.

Reading between the lines: If simplification isn’t the answer, what is?

The most effective way to help students read complex texts is to teach them how to read complex texts.

That means:

• Building background knowledge
• Teaching vocabulary in context
• Modeling reading strategies
• Providing scaffolds

A 2018 synthesis by Amendum, Conradi, and Hiebert found that when students received support – like pre-teaching vocabulary or guiding reading through discussion – the difficulty level of the text did not impact comprehension outcomes.

The takeaway? How students read (with support and strategy) matters more than what they read (in terms of text level).

Turning the page: What we do at Stile

At Stile, we intentionally preserve the richness of scientific language – while making it accessible to all students – through carefully designed, research-informed scaffolds. Here’s how we support students:

• Audio narration with word-by-word highlighting: Boosts fluency, especially for ELLs and students with reading difficulties. (Rasinski, 2012)
• Visuals and multiple representations: Reinforces key concepts and reduces reliance on text alone. (Ainsworth, 2006)
• Stile X workbooks: Targeted comprehension activities teach students how to unpack complex language and make meaning from what they read, and write their own definitions for words. (National Reading Panel, 2000)
• Flashcards and Interactive Glossary Quizzes: The flashcards and Interactive Glossary Quizzes included in Stile X help students to master and consolidate key terminology. Scientific vocabulary is essential for reading comprehension, especially in content areas like science. When students don’t understand key terminology, they struggle to make sense of texts – even if they can decode the words.(Nagy, W., & Townsend, D, 2012)
• On-hover glossary definitions: Support real-time vocabulary development and keep students engaged in the text. (Nation, 2001)
• We always use simple, clear succinct language in our text and questions. 

For students to develop proficiency in science, they need instructional materials that use clear language, avoid unnecessary complexity, and present information in manageable chunks to support understanding. We always use short sentences, introduce only one new topic per sentence, and always define the scientific term before we say it’s first occurrence in our lessons. We also use etymology to break down some new science terms.

(A Framework for K–12 Science Education, 2012)

Collaborative learning routines

Our Engagement Strategies include over 20 structured routines that build understanding through peer discussion and dialogue. (Gillies, 2016)

These approaches are underpinned by Universal Design for Learning (UDL) principles (CAST, 2018) and culturally responsive teaching – ensuring all students can access rich, meaningful content.

Bookmark these strategies: What you can do

You can amplify these supports in your own classroom through:

Pre-teaching key vocabulary and conceptsUse tools like Stile X flashcards or glossary quizzes to front-load key terms. This builds confidence before students encounter complex texts.

Repeated oral reading to build fluency Incorporate strategies like choral, echo, or paired reading. Our Stile Academy module on whole-class reading strategies unpacks how you can apply these in your science classroom.

Using Lexile adjustments selectivelyFor students significantly below level, use a readability tool or AI platform to adjust complexity while maintaining content integrity.

Build background knowledge Stile’s introductory lessons help activate prior knowledge and set students up for success before they dive into text-heavy material.

Encourage productive struggleFrame complexity as a challenge to be embraced, not avoided. With support, students can engage deeply and build long-term resilience.

You can find out more about how Stile supports ELL students and emerging readers in the Literacy Lifter Training module here.

The final chapter

Lowering lexile levels might make a text easier to read – but providing intentional scaffolds and helping students develop reading strategies is far more effective when when it comes to getting students to engage with grade-level content and develop the skills they need for the future.

At Stile, we believe no student should miss out on rigorous science content because of the language. With in-platform supports and strong teaching, every student can access – and thrive in – high-level science learning.

We focus on shifting the question from:“How can we change the text to fit the student?” to“How can we equip the student to access the text?”

This mindset supports the development of disciplinary literacy – helping students read, write, and think like scientists. And that’s a skill that serves them long after the lesson ends.

References

Ainsworth, S. (2006). DeFT: A conceptual framework for considering learning with multiple representations. Learning and Instruction, 16(3), 183–198.

Amendum, S. J., Conradi, K., & Hiebert, E. H. (2018). Does text complexity matter in the elementary grades? A research synthesis of text difficulty and elementary students’ reading fluency and comprehension. Educational Psychology Review, 30(2), 479–507.

CAST. (2018). Universal Design for Learning Guidelines version 2.2. CAST, Inc.

Gillies, R. M. (2016). Cooperative learning: Review of research and practice. Australian Journal of Teacher Education, 41(3), 39–54.

Lupo, S. M., Tortorelli, L. S., Invernizzi, M., & Ryoo, J. H. (2019). An exploration of text difficulty and knowledge support on adolescents’ comprehension. Reading Research Quarterly, 54(4), 457–479.

National Reading Panel. (2000). Teaching children to read: An evidence-based assessment of the scientific research literature on reading and its implications for reading instruction. Washington, DC: National Institute of Child Health and Human Development.

National Research Council. (2012). A framework for K–12 science education: Practices, crosscutting concepts, and core ideas. The National Academies Press. 

Nagy, W., & Townsend, D. (2012). Words as tools: Learning academic vocabulary as language acquisition. Reading Research Quarterly, 47(1), 91–108. 

Nation, I. S. P. (2001). Learning vocabulary in another language. Cambridge University Press.

O’Connor, R. E., Swanson, H. L., & Geraghty, C. (2010). Improvement in reading rate under independent and difficult text levels: Influences on word and comprehension skills. Journal of Educational Psychology, 102(1), 1–19.

Rasinski, T. V. (2012). Why reading fluency should be hot. The Reading Teacher, 65(8), 516–522.

Shanahan, T. (2014). Should we teach students at their reading levels?. Shanahan on Literacy

Snow, C. E. (2010). Academic language and the challenge of reading for learning about science. Science, 328(5977), 450–452. https://doi.org/10.1126/science.1182592

Strohmaier, A. R., Ehmke, T., Härtig, H., & Leiss, D. (2023). On the role of linguistic features for comprehension and learning from STEM texts: A meta-analysis. Preprint. ResearchGate.