Near the beginning of his book, David Didau says he doesn’t actually want to convince you that everything you know about education is wrong (though a fair amount of it actually is), but rather “that you will consider the implications of being wrong and consider what you would do differently if your most cherished beliefs about education turned out not to be true.” He spends a good portion of the book exploring why we have a tendency to stubbornly believe what we do, but then he explodes some of the most commonly-held beliefs in P-12 education.
Didau, who is from England, is a former teacher and a devotee of education psychology. As formative assessment guru Dylan Wiliam notes in his introduction to Didau’s 2015 book, What If Everything You Knew About Education Was Wrong?, the practice of education in recent years seems remarkably disconnected from what research actually reveals about the way we learn. Didau uses that research to challenge a host of ideas about instruction and assessment and offers a robust defense for a rather traditional approach to learning: knowledgeable teachers carefully modeling and guiding students through supported practice, revisiting challenging, domain-specific concepts until students have become experts in their own right.
According to Didau, if there’s one overarching misconception about education, it’s that we can observe short-term, incremental learning in students. “We teach, children learn,” Didau says of our false assumptions. “That’s the input/output myth.” Research on learning reveals that the process is far more complicated, Didau argues. In our obsession with short-term learning gains, we mistake “performance” - the ability to mimic a skill or concept - for real learning. Information can be forced into short-term memory over brief periods of time, but it doesn’t last. Thus the experience of every teacher: today students seem to understand the lesson, but tomorrow they’ll be as clueless as if I had never taught it at all.
Didau shows how forgetting is actually an essential part of learning. Unless a learning experience is imbued with a very high degree of emotional content or connection, new information usually has to be taught - and forgotten - several times for it to become embedded in long-term memory. Real learning takes place when new knowledge becomes linked to an existing schema - a mental framework of understand a complex web of information - or when schema are completely rearranged into new patterns to incorporate added content.
The implications of this understanding of learning are considerable. Didau is critical of many current practices of formative assessment, which seek to determine whether students have attained short-term mastery of a concept. Relying on students correctly answering formative assessment questions or tasks can be misleading, especially if the teacher assumes these correct answers means she can “move on” and be done with the concept. “If they answer your questions correctly, it means very little,” Didau says. “Who cares what they know at the end of the lesson. Better to assume that they are likely to forget it.”
Didau advocates a practice he calls “interleaving,” or intentionally reteaching key concepts while increasing the amount of time after each lesson. Not every concept or skill would need to be addressed through interleaving, but only those he calls threshold concepts, or those key understandings that students often struggle to master and upon which further progress in that subject depends. For example, Didau suggests gravity in physics, evolutionary theory in biology, opportunity cost in economics, and deconstruction in literature as possible threshold concepts for each discipline. Each subject might have several more threshold concepts depending on the grade level or developmental level of the students.
That these concepts are difficult to master explains why they are linchpins to deeper learning. The key goal of lesson planning should be to make sure every student is engaged in productive struggle with new material, because that’s where maximum learning takes place. Teachers should be assisting students in moving from a novice to an expert level (as developmentally appropriate) relative to their subjects.
While all of the above may sound like common sense, much of educational practice in recent decades stands in the way of the kind of rich, content-specific, and teacher-led instruction Didau is advocating. In fact, Didau positions the teacher as essential player in the learning process (very much the “sage on the stage” and not merely the “guide on the side”). In contrast to teaching approaches that place a major emphasis on student agency, collaborative learning, and “real-world relevancy” (whatever that means), Didau argues for a traditional model of instruction whereby the teacher as content-area expert explains new material, models new skill and application of knowledge, and carefully directs students through scaffolded levels of practice until independence is achieved.
Didau doesn’t necessarily reject project-based learning, group work, or “21st century skills” as wastes of time, but argues that spending energy on these strategies is far less effective and efficient than teacher-led instruction. Lest the reader think Didau’s methods would lead to rote memorization of facts, he presents a powerful argument that embedding new knowledge into students long-term memory is inseparable from teaching them how to think critically and creatively. “Creativity requires form,” he argues, illustrating how masterful artists spend years learning techniques and styles so that they can actually deviate from them.
As an advocate for formative assessment strategies, I found What If Everything You Knew About Education Was Wrong? compelling on multiple levels. Didau offers several pages of his book to formative assessment expert Dylan Wiliam, who agrees with Didau that there are many ways of oversimplifying and misusing formative assessment while still making a strong case that, whatever its limitations, teachers and students benefit from having more data about their learning progress than less.
Didau does not argue against assessment, but shifts the emphasis in how assessment is used. Specifically, he argues that regular testing of previously-taught material is itself one of the most powerful means of helping students relearn and therefore master new knowledge. So he advocates for less re-teaching and lots more retesting of previously-taught material.
Related to this, I found Didau’s ideas challenging to my keen interest in helping teachers create more personalized learning environments. I’ve recently become concerned about some of the excesses in the personalized learning movement that have de-emphasized the important role of knowledge in favor of teaching generic skills (as if those could be separated from domain-specific content), but still feel that instruction needs to be far more directed to individual students’ readiness levels relative to a clear and rigorous curriculum. But if Didau is correct, it’s far more difficult to actually establish a child’s readiness level that I assumed, and students may actually benefit greatly from being regularly reintroduced to content they or their teacher think they have already mastered.
Perhaps there is more room here for whole class instruction than I’ve previously considered, and perhaps the key really is ensuring that no matter how many times a student has encountered a concept, the learning must be deliberately difficult enough to cause the student to struggle, but always with the actual possibility of supported success.
I believe all teachers and school administrators would benefit from reading What If Everything You Knew About Education Was Wrong? and struggling with the questions David Didau raises. Alongside recent works by E. D. Hirsch (reviewed here) and Daisy Christodoulou (reviewed here), Didau’s book makes a strong case for a rigorous and well-planned curriculum and thoughtful teacher-led classrooms.
Usual disclaimer: All views expressed on this website are mine alone and do not reflect the opinions of Western Kentucky University (where I serve as associate professor of educational administration, leadership, and research) or the Kentucky Board of Education (where I serve as a member).