Have you ever listened to a student read aloud fluently about something—say, the life cycle of sea turtles—only to discover afterward that they couldn’t explain a single thing about…the life cycle of sea turtles? It’s a familiar classroom moment, and it reveals how easy it is to misunderstand what comprehension really is.

Comprehension is often framed only as the product of reading: the answers students give when asked to find the main idea, identify a theme, or summarize a passage.

But the Science of Reading tells us that comprehension is more than an outcome. Comprehension is also a dynamic process that unfolds as readers move through a text, powered by the interactions among words on the page and the knowledge and reasoning they bring to it. That’s why we like to think of it as the heartbeat of literacy.

Why comprehension is both product and process

For decades, much of classroom instruction has focused on language comprehension products: the demonstrations of understanding that happen after reading. Those are important, but they don’t tell the whole story.

That’s because products depend on processes. If students do not build a coherent mental model of what they’re reading—while they’re reading—they may succeed at reading, but not at comprehending.

This is the missing link that researchers like Hugh Catts, Ph.D., and Jane Oakhill, Ph.D., have revealed: Comprehension isn’t something readers suddenly have at the end of a passage. It’s also something they do all along the way.

What comprehension processes look like

Comprehension processes are the mental moves students make to construct meaning as they read. All students need explicit instruction and practice in order to learn to do this automatically. Some of the most important processes include:

• Inference-making: Filling in gaps the author leaves unsaid. If a story says “Carlos forgot his umbrella and got wet,” readers must supply the missing piece: It rained.
• Anaphora resolution: Figuring out who pronouns such as he or she refer to. For instance, in a passage where “Charmaine passed the ball to Kendra, and she scored,” not all readers may track that she refers to Kendra.
• Monitoring meaning: Noticing when something doesn’t make sense and rereading to fix it. Think of a student breezing through a science lab procedure but not realizing they’ve misunderstood a key step.
• Recognizing connectives: Using words like because, however, or meanwhile to understand how ideas fit together in a text about history, math, or literature.
• Visualizing: Building a mental picture—whether that’s of how a caterpillar becomes a butterfly, or how a character’s feelings shift across a story.

When these processes don’t happen, comprehension breaks down—even for students who can decode fluently. That’s why teaching comprehension can’t mean just assigning comprehension questions. It has to mean teaching students how to think with text in real time.

The role of knowledge and writing

Processes don’t exist in isolation. They depend on, and are strengthened by, what students already know and what they can express in writing.

• Knowledge: The more background students bring to a text, the easier it is for them to make inferences and connect ideas. A child who already knows a little about baseball will understand a passage about a pitcher’s strategy much more readily than one encountering the game for the first time.

• Writing: Writing about reading reinforces comprehension. When students summarize a biography in their own words, draft a response to a novel, or synthesize ideas from multiple sources, they are practicing the very processes—like making connections and organizing ideas—that skilled readers rely on.

This interplay—reading feeding knowledge, knowledge feeding comprehension, writing reinforcing both—creates a cycle of literacy growth that goes far beyond the end-of-text quiz.

Rethinking classroom practice

Working on individual comprehension skills can help in the short term. But long-term literacy success—for all students—requires explicit instruction and practice in all the comprehension processes needed to build comprehension products.

So what does it mean to teach comprehension as a process, not just a product?

Weaving effective instruction in comprehension strategies into everyday literacy work. A few examples:

• Model your thinking. Pause mid-reading to ask, “Who does she refer to here?” or “That didn’t make sense—let’s go back.”

• Highlight connectives. Teach words like although or consequently explicitly, showing how they signal relationships between ideas.

• Promote monitoring. Encourage students to ask themselves, “Does this make sense?” and to reread when it doesn’t.

• Build knowledge deliberately. Use content-rich texts in science, history, and the arts to give students the context they need for stronger comprehension.

• Pair reading with writing. Even short written responses—“Why do you think the character acted that way?”—help solidify understanding and make comprehension processes visible.

These practices shift comprehension instruction from an after-the-fact check to an in-the-moment skill set students can carry into every subject.

Want to dig deeper?

Expanding our understanding of comprehension as both product and process is one of the most important shifts the Science of Reading has brought to literacy instruction. It reminds us that comprehension isn’t just a mysterious outcome at the end of reading—it’s the ongoing work of making meaning along the way.

To help educators explore this shift, we’ve created the new Science of Reading: Comprehension 101 bundle. These resources break down the research and provide strategies you can use right away. When we teach comprehension as the ongoing process it truly is, we keep the heartbeat of literacy strong for every reader.

Inside, you’ll find the following resources:

• Our anchor ebook: Understanding Comprehension: The Heartbeat of Literacy
• Infographic: The missing link in reading comprehension
• Ebook: Knowledge, Reading, and Writing: The Secret Recipe for Literacy Success
• Podcast: “Science of Reading Essentials: Comprehension” episode and listening guide
• Webinar: Rethinking Reading Comprehension: Reflections on Hugh Catts’ and Jane Oakhill’s Research