Why principles beat practices every time

What CPD gets wrong, and what it costs us

There is a scene that will be familiar to many teachers. A new initiative arrives, backed by research, explained in a staff meeting, and condensed into a set of required practices. Do this in every lesson. Make sure it is visible in books. It will be looked for in observations.

And so teachers do it. They perform it, at least. The sticky notes go up. The exit tickets go out. The learning objectives are written in a particular place on the board. The form is preserved. The thinking behind it, mostly, is not.

This is cargo cult teaching. The term comes from the behaviour of Pacific island communities who, having watched supply planes land during the Second World War, built wooden runways and wore headphones made of coconut shells once the planes had gone. The ritual was perfect. The understanding of what made it work was absent. The planes did not come back.

The problem with specifying practices

When CPD and T&L policy focus on specifying practices, this is what tends to happen. Teachers learn what to do without learning why it works. They follow the script in contexts where the script fits, and they follow it equally dutifully in contexts where it does not. The practice becomes compliance rather than craft.

This is not the fault of teachers. It is the predictable consequence of how the training was structured. If you tell someone to use cold calling rather than explaining that the goal is to keep all pupils accountable and thinking, they will cold call. They will cold call in lessons where it creates anxiety rather than challenge. They will cold call when the class needs something different, because they were not given the tools to know when to choose otherwise.

The practice, separated from its principle, cannot adapt. And teaching is nothing if not a constant demand for adaptation.

David Berliner’s research on expert teachers helps explain why. Drawing on the Dreyfus brothers’ model of skill acquisition, Berliner identifies five stages in the development of teaching expertise, from novice through to expert. At the novice stage, teachers rely on context-free rules and exhibit rigid, rule-conforming behaviour. This is appropriate and necessary for beginners. The problem arises when CPD keeps experienced teachers operating at this level by design, giving them rules to follow rather than understanding to develop.

Expert teachers, Berliner shows, work very differently. They are more opportunistic and flexible in their teaching, more sensitive to task demands and the social situation of the classroom, and they represent problems in qualitatively different ways than novices. They develop what Berliner calls contextualised knowledge: experts can teach based upon contextualised thinking, while novices teach regardless of content or context. This is why experts can respond quickly and intuitively to events, and why novices cannot be flexible in their teaching. Researchers measuring flexibility directly found significant differences in favour of expert teachers on adaptability and responsiveness to students, and expert teachers were shown to have a kind of plan independence when teaching in areas of their pedagogical strength.

The implication is stark. A CPD model built around practices is, by Berliner’s own framework, keeping teachers at the novice end of the developmental spectrum indefinitely. It does not accelerate expertise. It structurally prevents it.

Maps, not routes

A useful analogy: there is a difference between giving someone a route and giving them a map. A route gets you to one place. Follow it carefully and you will arrive, at least if nothing on the road has changed. But a map lets you navigate anywhere. It lets you respond to a road closure, find a shortcut, or recognise when the destination itself needs to change.

Principles are maps. Practices are routes.

A teacher who understands that worked examples should make expert thinking visible, not just display a finished product, can apply that principle across subjects, year groups and learning contexts. They can recognise when a model is working and when it has become a crutch. A teacher who has only been told to use worked examples has a route, and they will follow it whether or not it leads anywhere useful.

Lee Shulman’s concept of pedagogical content knowledge deepens this point. Shulman argued that the most important knowledge a teacher holds is that special amalgam of content and pedagogy: an understanding of how particular topics, problems, or issues are organised, represented, and adapted to the diverse interests and abilities of learners. This kind of knowledge is inherently contextual, subject-specific, and developed through experience and understanding. It cannot be captured in a generic checklist. A T&L policy that specifies practices across all subjects is, by definition, operating at a level of abstraction that strips away precisely what Shulman identified as most valuable.

What this costs the profession

There is a deeper issue here, and it concerns professionalism itself.

A profession is defined not merely by its technical skills but by the body of knowledge its practitioners hold and the judgement required to apply it. Doctors do not follow protocols without understanding pathology. Lawyers do not apply precedent without understanding the principles behind it. When we reduce teaching to a set of specified practices, we treat it as a technical trade rather than a learned profession. We say, in effect, that the thinking has already been done, and teachers need only carry it out.

Mark Priestley, Gert Biesta and Sarah Robinson, in their ecological account of teacher agency, argue that over-regulation of this kind does real damage. Too much regulation, or the wrong type, can stifle innovation and lead to instrumental curriculum making in schools — the tick-the-box approaches that mistake compliance for competence. Importantly, Priestley does not simply argue for teacher freedom. He is careful to note that agency without resources is insufficient. Excellent teaching requires relational resources afforded by professional networks, cultural resources afforded by engagement with research, and crucially the time and space for teachers to work as curriculum makers rather than curriculum deliverers. A CPD culture built on prescribed practices tends to deny teachers all three.

This is demeaning to the people we are asking to do the work. It is also, over time, damaging to the work itself.

Who writes the next playbook?

Here is the question nobody seems to be asking: if teachers only ever follow a playbook, who understands enough to write the next one?

Every cohort of new teachers trained primarily in practices, without the principles beneath them, represents a narrowing of the profession’s intellectual base. Lawrence Stenhouse, whose work on curriculum development remains one of the most important contributions to thinking about teacher professionalism, argued that curriculum development has little chance of success unless it involves teachers in exploring their own practice through research and inquiry. He placed the teacher as researcher at the heart of what it means to be a professional educator. His point was not merely about individual development. It was about the collective capacity of the profession to think, to interrogate, to improve.

That collective capacity cannot be sustained if each generation inherits only practices and never principles. The people who did understand the principles, who built those policies from research and thought, eventually move on. What remains is a set of rituals that nobody can interrogate, update, or adapt to new circumstances. Schools begin to look consistent. Lesson observations produce the expected forms. And gradually, quietly, the capacity to think about teaching well begins to atrophy, because it was never cultivated in the first place.

This is not hypothetical. It is the direction of travel in any system that mistakes compliance for competence. It is also, as Berliner’s research reminds us, the opposite of how expertise develops. Expert teachers, at the highest stages of professional development, exhibit what he calls plan independence: they are not bound by the script because they understand deeply enough to go beyond it. A profession that trains its teachers away from that kind of understanding is not improving its practice. It is hollowing out its future.

What good CPD actually does

None of this is an argument against practices. It is an argument about the order of things.

Practices, taught well, are illustrations of principles in action. They are examples, not edicts. When a teacher learns a technique, they should simultaneously be learning what problem it solves, what the evidence says about why it works, and what conditions are required for it to work well. They should be learning to read a teaching situation and ask which principle applies here, and then to select or adapt a practice accordingly.

Priestley’s caveat is worth holding onto here. Teacher autonomy without understanding is not the goal either. The aim is what he calls genuine agency: teachers who are research-literate, professionally connected, and equipped with the conceptual resources to make principled decisions. That requires CPD that is serious about developing knowledge, not just securing compliance.

This is harder to observe. It does not produce a neat checklist. It cannot be reduced to a lesson visit rubric. But it is what teaching actually is when it is done by someone who has been trusted to think.

The question for school leaders is whether that is what they want. Whether they want teachers who can follow a playbook, or teachers who understand the game well enough to write one.

The answer to that question determines everything about how you run CPD.

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References

Berliner, D.C. (1986). In pursuit of the expert pedagogue. Educational Researcher, 15(7), 5–13.

Berliner, D.C. (2001). Learning about and learning from expert teachers. International Journal of Educational Research, 35, 463–482.

Berliner, D.C. (2004). Describing the behavior and documenting the accomplishments of expert teachers. Bulletin of Science, Technology and Society, 24(3), 200–212.

Dreyfus, H.L. and Dreyfus, S.E. (1986). Mind Over Machine: The Power of Human Intuition and Expertise in the Era of the Computer. New York: Free Press.

Priestley, M., Biesta, G.J.J. and Robinson, S. (2015). Teacher Agency: An Ecological Approach. London: Bloomsbury.

Shulman, L.S. (1986). Those who understand: Knowledge growth in teaching. Educational Researcher, 15(2), 4–14.

Shulman, L.S. (1987). Knowledge and teaching: Foundations of the new reform. Harvard Educational Review, 57(1), 1–22.

Stenhouse, L. (1975). An Introduction to Curriculum Research and Development. London: Heinemann.