Given the time constraints that all teachers face, what are the most effective strategies to help our students with reading comprehension? Should we focus on particular reading strategies: say — finding the main idea of a passage, predicting what will come next, visualizing the scene? Or do we serve students better by building overall historical, cultural, and scientific knowledge: say — the development of the silk road, an understanding of erosion, the innovations of Martha Graham?
Like so many debates in education, this one prompts heated — often exasperated — debates.
A recent study considers such questions.
Faith Bandler, and Beyond
A group of Australian researchers worked with 8-year-olds at a relatively affluent school. Over the span of eight weeks, students learned about several topics: artifacts, fossil fuels, a famous Australian voting-rights activist named Faith Bandler, Nelson Mandela, and so forth. Typically, the sequence went like this:
- Teachers taught a multi-class unit on one topic. At the end of the unit, students took a short-answer quiz on that topic.
- Soon after, students read a passage related to the topic. Once again, students took a test.
- Some of the questions simply tested knowledge from the reading passage.
- Others required drawing inferences based on the reading passage.
- Still others required drawing inferences from the preceding unit taught by the classroom teacher.
By following all these steps, researchers could consider important questions:
- How much did prior knowledge from the unit help students understand the reading passage?
- And: did the individual student’s skill at reading matter?
I should also describe one important variation from this typical sequence. In most cases, the reading passage and test came soon after the classroom unit on a topic. With two topics, the teacher waited four weeks after the classroom unit for students to read the related passage and take a test on it. For this reason, researchers could answer another important question:
- Do the benefits of prior knowledge fade within four weeks?
Given all these steps and calculations, what did the researchers conclude?
Certainty, and Uncertainty
Because this study measured so many different variables in so many circumstances, I’m not going to report numerical results. (You can find all the data here if you’re curious.) Instead, I want to focus on plausible conclusions.
More broadly, I want to push back on strong claims I’ve been hearing about this study. When I first came across it, the quick headlines read — in effect — that this study shows conclusively the importance of prior knowledge for reading comprehension. By implication, this study has been offered as a way to support a “knowledge-rich” curriculum. I’m not persuaded by that reading of these data; let me try to explain why.
Conclusion #1: As you recall, on two occasions students waited four weeks after the unit before they read the related passage and took the follow-up test. How did those students do on the reading test compared to their peers who read the passage right away?
Sure enough, after a four week gap, the benefits of that prior knowledge had begun to fade. Students in the waiting-four-weeks group scored lower than the read-right-away group.
On the one hand, this finding makes great sense. I’m not surprised — and I doubt that you are — that students who have background knowledge fresh in mind will understand a reading passage better than students who haven’t thought about the topic in the last month.
On the other hand, this conclusion cuts two ways.
- Yes: it highlights the importance of prior knowledge.
- However — and this is a big “however” — it doesn’t necessarily support the broad claims of a knowledge-rich curriculum. These students didn’t benefit from having gotten relevant background knowledge at some point in the past. They benefited from getting that knowledge immediately before reading.
In their strongest version, claims supporting a knowledge-rich curriculum emphasize that getting knowledge will benefit reading comprehension at some point in the future. This study does not support that claim — at least if that “point in the future” is a month or more after initial instruction.
At a minimum, this finding suggests that a knowledge-rich curriculum should include frequent review in order to benefit future reading comprehension.
More Uncertainty
If I put several parts of this study together, I can also summarize one theme this way:
Conclusion #2: Strong readers did better at almost everything.
- They knew more topic content at the end of the classroom lessons than the weaker readers did.
- They scored higher on the factual knowledge part of the reading tests.
- They were more successful at drawing inferences on the reading tests.
- Whereas the four week delay reduced scores for weaker readers, that delay did NOT (statistically significantly) reduce scores for stronger readers.
Let’s go back to the first of those bullet points: “stronger readers knew more topic content at the end of the classroom lessons than the weaker readers did.” This result strikes me as very puzzling.
I understand why weaker readers learn less from reading, but why might they have learned less from teaching? Did the strong readers already know more about these topics before the lessons began? (There was no pretest, so we don’t know.) Did the classroom lessons rely heavily on reading? Is direct instruction less beneficial to weak readers for some obscure reason? I just don’t see an obvious reason that those two cognitive capacities — “ability to read” and “ability to learn from classroom lessons” — should be related.
To make this point a different way: this study’s title is “The Importance of Knowledge for Reading Comprehension.” I think it makes that case, although in a limited way. Based on the conclusions I’ve just listed, I wonder if a better title might be: “The Importance of Skilled Reading for Academic Success.” Or an even more accurate title: “Skilled Reading is a Good Proxy for General Academic Success (but We Don’t Really Know Exactly Why).”
To be clear, I think this study shows that active prior knowledge enhances reading comprehension. (Those benefits dissipate with time, as that prior knowledge becomes less “active.”) But it also points to a bigger question: how does skilled reading connect to — or cause, or result from — other categories of academic life: motivation, vocabulary development, self-efficacy, working memory capacity, attention, and so forth?
Both this blog post and the study that inspired it started by focusing on background knowledge as an important variable in reading skill. I’ve ended up more curious about the relationship between reading and academic success more broadly. I’m sure that background knowledge matters — and this study has left me equally sure that there’s much more to the story…
Smith, R. J., Snow, P. C., Serry, T. A., & Hammond, L. S. (2026). The Importance of Knowledge for Reading Comprehension: A Quasi-Experimental Investigation. Reading Psychology, 1-27.
