Basing something on a single study is never smart. But if two large and solid studies say something similar, then it is still advisable to remain cautious, but still look at everything seriously. In recent weeks, two similar studies have been published on the role of (background) knowledge in reading comprehension. This role would be enormous and have important consequences for (in)equal opportunities.

Of course, we have known for longer than today that knowledge is important for reading comprehension, but the studies show that it may be more important than thought compared to learning strategies.

The first longitudinal study received less attention than the second, but I approached them chronologically. The research by James Kim and colleagues developed a knowledge-rich curriculum called More. It investigated this effect in 30 schools on just under 3000 students in a randomized controller trial comparing children who did get the curriculum with children who did not get it. The research shows some striking results. This reduces inequality, reduces the negative effect of a long summer holiday and attracts all readers (strong, weaker,…) to benefit from it. And yes, the research also confirms that reading on paper is better than reading on screen.

The second study is by David Grissmer and many colleagues, including Dan Willingham, which created the necessary buzz. It is a longitudinal study that looked at the effect of introducing a knowledge-rich curriculum in charter schools in Denver, comparing children who did end up in the schools via lottery with the students who did not end up in them. The students with the knowledge-rich curriculum scored 16 percentage points higher than the comparison group. This is a huge increase, but also striking: the inequality in these schools decreased for the different subjects. Please note: this study is still a working paper!

Both studies also show a transfer effect. Transfer is what we want, especially in reading comprehension. The intention is that you can also get the essence of new texts on a new subject.

If both studies seem to make one thing clear, it is the importance of knowledge in education, especially for equal opportunities. It is an advantage that both studies have used two different knowledge-rich curricula because that will probably be the most important question: what knowledge is needed in such a curriculum. The Core Curriculum developed by ED Hirsch and used in the second study has overlaps, but also differences from the MORE curriculum from the second.