How important is prior knowledge and vocabulary to reading comprehension for struggling readers?

MORE IMPORTANT, as it turns out, than I ever thought.

—MORE IMPORTANT than main idea, supporting details, cause/effect, predicting, clarifying, questioning, summarizing…all individual skills that I have spent my career teaching as a reading specialist.

A recent meta-analysis¹ of reading comprehension has made me question my use of instructional time.

For example, read this:

The mammalian CAD gene codes for a 240-kDa multifunctional protein that catalyzes the first three steps of de novo pyrimidine biosynthesis. Previously, the longest cDNA construct available was missing approximately 500 bp of coding sequence at the 5’ end, thereby lacking the sequence to encode the entire carbamylphosphate synthetase domain….²

Did you comprehend this scientific excerpt?

Unless you understood the vocabulary before you read it, and unless you had a previous schema for microbiology in your brain, even if not complete, you could not comprehend it adequately.

As content area teachers teach, most struggling readers have only blurry understanding of much of the content specific vocabulary, and an even more vague idea of where to place information in the very hazy diagram in their heads.

The brain remembers in patterns. If we want our struggling students to remember content that we teach them, we need to ensure that they are familiar, not only with the relevant vocabulary, but also, that they can fit the incoming information into a framework already their brains, BEFORE we teach the specific content.

A famous study³ asked junior high students to read a selection about baseball. They were divided into four groups according to high and low reading ability and high and low prior knowledge about baseball. The research concluded the most powerful effect for comprehension was the prior knowledge group, not the higher reading ability group.

What do the meta-analyses tell us about how best to use our instructional time?

Content area teachers should always include some pre-teaching BEFORE assigning a chapter of a textbook, and not just vocabulary. Provide a video, a novel excerpt, or a letter from a particular era or scientist BEFORE reading to improve prior knowledge. Relating the impending information in an explicit way to a frame that has previously been taught would be especially helpful before new content is introduced. At a minimum, review the relevant concepts previously taught in class.

Please do not leave out this pre-teaching step, or you might lose all or most of the struggling readers in your class.

Repetition is also good for struggling readers. One comprehension aid that I have used for most of my career is reading the questions that will have to be answered with students BEFORE actually reading the text.

Struggling readers (more than half of eighth graders, according to the 2022 National Assessment of Educational Progress (NAEP),⁴ might learn more with a chart, story map, diagram, or some sort of graphic representation BEFORE being asked to read text so that they have a schema in which to begin to fit the information.

English teachers, how about a sample diagram (Remember that?) before teaching a grammar skill?

Also, read my Free Tip on a great Study Method which students can easily learn:

SQ3R Study Method

To improve student mindfulness, consider these two FREE Self-Help Tests:

Study Habits

Reading Habits

¹Think Again—Should Elementary Schools Teach Reading Comprehension

^{2 Excerpt from my daughter’s doctoral thesis}

³The Nation’s Report Card

Here are some interesting post from my friends at TBOTEMC:

How Important is Prior Knowledge, Really?