The Bolted-On Concept Trap: Why Your PYP Units Feel Like Traditional Lessons

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Erickson (2012) notes a trap. Concept-based learning units can miss the mark. Schools often add a concept to existing topics. For example, a unit on Ancient Egypt may appear complete. "Change" links to the central idea, but the concept does not guide inquiry.

The concept did not drive that unit. It was bolted on afterwards, like a label applied to a box that was already packed. Research on concept-based teaching shows an effect size of 0.93 on deep understanding when concepts genuinely drive the inquiry (Erickson et al., 2017), compared with near-zero transfer when concepts are appended to topic-based units retrospectively. The learners will spend three weeks learning about Egypt. They will learn about Egypt in English, in art, in maths. The concept of Change will appear on the word wall. It will be referenced in the final reflection. But it will not change how the learners think. It will not transfer. It will not, in Erickson and Lanning's (2014) terms, produce synergistic thinking: the cognitive interplay between concrete facts and abstract conceptual understanding that separates genuine inquiry from sophisticated topic work.

Thinking Frameworks connect ideas and lessons. Eight cognitive operations help learners apply knowledge to tasks. A five-point checklist helps diagnose learning needs (author, date). This article provides a useful solution to a common issue (author, date).

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The Two-Dimensional Problem

Erickson (date not provided) named "two-dimensional curriculum" to guide IB concept learning. It includes both content and skills. Learners gain knowledge and practise key processes. Both elements are important for learners. However, neither element alone fully prepares them.

Erickson (2002) says conceptual understanding involves learners building big ideas with facts. This creates a Structure of Knowledge. Learners move fluidly between facts and concepts. This helps them construct understanding and examine new information (Erickson, 2002).

Concept training often focuses on vocab, missing planning (Erickson, 2002). Teachers learn IB concepts (Form, Function, Causation, Change, Connection, Perspective, Responsibility). They add these to planners. However, topics still control content if planners aren't concept-led (Erickson, Lanning & French, 2017).

Units meet the checklist, yet encourage only topic-based thought. Learners finish an "Ancient Egypt: Change" unit knowing about Egypt. However, they may not grasp transferable concepts of change.

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What Concept-Driven Actually Means

Erickson and Lanning (2014) say concepts are abstract, timeless, and transferable. "Change" is a concept. "The Egyptians changed" is not. It uses "change" as a verb. What understanding about Change will learners retain beyond Egypt?

IB PYP units use central ideas, not just topics, to express generalisations. These generalisations connect concepts, making broader claims. For example, "Systems depend on balanced parts" (Erickson, 2002). Learners can test this transferable idea. Use examples like Egyptian irrigation or the school (Wiggins & McTighe, 2005). Rainforests and governments can also demonstrate this concept (Costa & Kallick, 2008). The topic reveals the generalisation.

This distinction matters because of what Erickson calls synergistic thinking. When a learner genuinely encounters a concept through a concrete example, they do not simply learn about the example. They refine their understanding of the concept. The facts and the abstraction work on each other. The learner who uses the concept of Systems to analyse both a pharaoh's court and their school council is thinking at a qualitatively different level from the learner who knows facts about both.

Wiggins and McTighe's (2005) Understanding by Design framework makes the same point from a different direction. Enduring understandings, their term for the generalisations worth retaining, cannot be assessed with a quiz about facts. They require performance tasks that demand transfer: take what you understood here and apply it there. If you cannot write a transfer task for your central idea, you may not have a central idea.

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The 5 Warning Signs Your Unit Is Bolted-On

Teachers can use this checklist to spot learning issues. Each warning sign indicates a structural problem needing a specific solution. The checklist is for diagnosis, not grading.

Warning sign 1: The central idea reads like a topic sentence. "Ancient Egyptians built pyramids that changed their society" describes a topic. It contains a fact and a concept-word, but it makes a claim only about Egypt, at a specific time, in a specific place. A learner could not use it to think about anything else. The fix is to rewrite using the Central Idea formula: Concept A + Context + Concept B. "Human societies create structures that reflect and reinforce their values" uses Egypt as one possible vehicle but could equally carry a unit on modern architecture, religious buildings, or digital platforms.

Warning sign 2: Lines of inquiry are activities, not inquiry pathways. "How pyramids were built," "What the pyramids looked like," and "Why they were important" are research questions about Egypt. They are not inquiry pathways into the concept. Inquiry pathways for the generalisation above would look different: "What values do different societies express through their built environment?" and "How do power structures shape what gets built, preserved, or destroyed?" These questions cannot be answered by recalling facts. They require learners to think with the concept.

Warning sign 3: Assessment measures knowledge recall, not conceptual transfer. If the summative assessment task asks learners to write about Egypt, it is a topic assessment. A transfer task asks learners to apply their conceptual understanding to a new context. "Using what you now understand about how societies express values through structures, evaluate a building in your own community" is a transfer task. The Egyptian content is no longer the subject: it is the prior experience from which the learner draws.

Warning sign 4: The key concept could be swapped without changing the unit. Try this thought experiment: replace "Change" with "Connection" in your unit planner. Does the unit look substantially different? If not, the concept was not doing any structural work. In a genuinely concept-driven unit, the conceptual lens determines which aspects of the topic are foregrounded, which lines of inquiry are pursued, and which transfer tasks are relevant. Swapping the concept should produce a recognisably different unit.

Warning sign 5: Learners can answer "What did you learn?" but not "What did you understand?" This is the simplest diagnostic. Ask learners at the end of a unit to complete both sentences. The first invites knowledge recall. The second invites conceptual reflection. In a bolted-on unit, learners produce detailed answers to the first question and vague or absent answers to the second. "I understood that things change" is not a conceptual understanding. "I understood that societies use physical structures both to maintain power and to signal what they value, and that this pattern shows up in very different times and places" is the beginning of one.

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The Central Idea Formula

Erickson and Lanning's (2014) formula helps fix central ideas: Concept A + Context + Concept B. The formula needs a claim. The claim should link two concepts using a contextual relationship. The relationship must be valid across contexts.

Topic-driven version	Concept-driven version	Why the second works
Ancient Egyptians built pyramids that changed their civilisation.	Human societies create structures that reflect and reinforce the values of those in power.	Connects Systems and Values; transferable to any built environment across time.
The water cycle describes how water moves around the Earth.	Natural systems maintain balance through cyclical processes that distribute resources.	Connects Systems and Balance; applies to water cycles, food webs, carbon cycles.
Communities have rules that help people live together.	Shared agreements shape the rights, responsibilities, and identity of a community.	Connects Agreement, Rights, and Identity; transfers from school rules to national constitutions.
Migration has affected the culture of many countries.	When people move, they bring their cultural identity with them, transforming both their new community and themselves.	Connects Migration, Identity, and Transformation; applies to historical migration and contemporary displacement.

A practical test for any central idea: replace the specific topic with "people," "systems," or "communities" and check whether the idea still makes sense. If it does, you likely have a generalisation. If it collapses without the specific topic, you have a topic sentence.

Marschall and French (2018) suggest checking structure: central ideas should actively link concepts. A weak idea is "Change has many causes". Marschall and French (2018) say a strong idea is: "Economic factors speed social change faster than politics." This claim is specific and debatable.

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The Three-Tiered Questioning Framework

Erickson and Lanning's (2014) framework helps check inquiry lines lead learners to the central idea. Coordinators can use it to audit lines of inquiry. Ensure they build towards, not just around, the core concept.

Factual questions establish the knowledge base. They have correct answers that can be verified. "Which key concepts does the IB define?" and "What are the six IB PYP transdisciplinary themes?" are factual questions. They are necessary but not sufficient. A unit composed entirely of factual lines of inquiry is a research assignment, not an inquiry.

Conceptual questions push learners to build generalisations from facts. They cannot be answered by recalling information. They require learners to connect, compare, or evaluate. "How do the structures a society builds reflect its values?" is a conceptual question. It requires factual knowledge to answer, but the answer is a generalisation, not a fact. These questions are the engine of concept-driven inquiry.

Debatable questions sit at the top of the framework. They are provocative, open-ended, and do not have consensus answers. "Is it ever justified to destroy the physical structures of a past culture?" is debatable. These questions develop the perspective-taking and moral reasoning that are central to the IB Learner Profile. They also signal to learners that the inquiry matters beyond the classroom.

When auditing a unit's lines of inquiry, check that all three tiers are present and that the conceptual questions are genuinely conceptual, not disguised factual questions with the word "why" added. "Why did the Egyptians build pyramids?" is factual in disguise: it has a conventional historical answer. "Why do powerful groups in every era build monuments?" is genuinely conceptual.

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The Thinking Framework Fix

Naming the problem is straightforward. Fixing it in the classroom requires tools that make abstract concepts operational for learners, not just for curriculum designers. This is where the Thinking Framework enters.

Researchers (Marzano et al., 1988) identified eight cognitive operations. These operations (Compare, Classify, etc.) guide thinking with a concept. Learners get a label if you add a concept alone. When learners apply an operation to a concept, they gain a process.

Consider a Year 4 unit on "How We Organise Ourselves" with the key concept of Function. The bolted-on version: "Let us learn about how communities work. The concept is Function." The Thinking Framework version uses Part-Whole analysis as the cognitive procedure:

"Imagine every adult in our school disappeared for one day. Which roles would the community miss immediately? Which could wait a week? Use the Part-Whole operation to map which functions are essential and which are supporting. Now transfer this: what roles are essential in a hospital? What roles could a hospital survive without for a day?"

The Part-Whole operation gives learners a cognitive procedure for working with Function as a concept. They are not memorising what function means. They are using it to analyse, and then transferring that analysis to a new domain. The concept is doing structural work.

Each cognitive operation maps naturally onto specific conceptual work:

IB Key Concept	Thinking Framework operation	What learners do
Change	Sequence + Cause and Effect	Map the stages of a change process; identify what triggered each stage; transfer to a different change process.
Connection	Systems Thinking + Analogy	Map the connections within a system; identify which connections are essential; find analogous systems in different domains.
Causation	Cause and Effect + Compare	Distinguish proximate causes from underlying causes; compare two events to identify common causal patterns.
Form	Classify + Part-Whole	Identify the features that define a category; analyse how parts contribute to the defining whole.
Perspective	Perspective + Compare	Articulate how the same event or object is experienced differently from different standpoints; compare what each perspective reveals and conceals.
Responsibility	Perspective + Systems Thinking	Map who is affected by a decision and how; evaluate which actors have agency; consider systemic responsibilities beyond individual action.
Function	Part-Whole + Analogy	Map the role each part plays in the whole; find analogous functional structures in a different domain.

The Thinking Framework aids the IB Learner Profile practically. "Thinker" and "reflective" traits are often just mentioned, as noted by Costa and Kallick (2008). We build cognitive skills into activities so learners genuinely reflect, argue Fisher and Frey (2007). This makes them thinkers beyond assessment, suggest Ritchhart et al (2011).

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Before and After: Rewriting a Bolted-On Unit

The following example is based on a composite of real planning conversations with PYP coordinators. The original unit is not unusual: it would pass a standard planner review. The rewritten version addresses each of the five warning signs.

Original unit (bolted-on):

Learners explore rainforests. Rainforests change due to human actions. We'll ask: What are rainforests? Why do they matter? How do we harm them? What helps? Learners create conservation posters (Sharing the Planet). (Inspired by research such as Vygotsky, 1978; Bruner, 1966; Piaget, 1936).

Rewritten unit (concept-driven):

Sharing the Planet looks at interdependence. Human actions have wide effects on nature. Learners explore rainforest relationships to see system changes (Meadows, 2008). They debate resource rights. The final task: map a local ecosystem and argue about decisions, showing different views (Meadows, 2008).

Learners find the rewritten unit purposeful, not harder. The rainforest remains the context, but with a clear goal. Learners practise Systems, Interdependence, and Perspective. They transfer this thinking to new contexts like coral reefs (researchers, date). The old unit gave rainforest knowledge; the new unit gives transferable thinking.

Notice that the summative task changed fundamentally. The poster asked learners to recall and present information. The rewritten task asks learners to map, reason, and argue from multiple viewpoints. This is what Murdoch (2015) means when she writes about inquiry-based learning as a recursive process: the assessment task should require learners to use the conceptual understanding they have built, not describe the topic they have studied.

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The Coordinator's Audit Tool

The following ten questions give PYP coordinators a consistent framework for evaluating unit planners. Each question maps to one of the five warning signs and their associated fixes.

Central Idea audit:

1. Does the central idea make a claim that holds beyond the specific topic? (Replace the topic with a different example. Does the claim still work?)
2. Does it connect at least two abstract concepts through an active relationship? (Avoid passive voice and weak connectives like "is affected by.")
3. Is it free of specific places, people, and dates? (Proper nouns in a central idea usually signal a topic sentence.)

Lines of Inquiry audit:

4. Is there at least one genuinely factual line of inquiry that establishes necessary knowledge?
5. Is there at least one genuinely conceptual line of inquiry that cannot be answered by recalling information?
6. Is there at least one debatable line of inquiry that invites genuine disagreement?

Assessment audit:

7. Does the summative task require learners to apply their understanding to a new context, not just report on the topic studied?
8. Could the task be completed by a learner who simply researched the topic thoroughly, without ever engaging with the central idea? (If yes, it is not a transfer task.)

Concept audit:

9. Does swapping the key concept for a different one require a substantially different unit? (If not, the concept is decorative.)
10. Is there at least one learning activity in each phase that uses a specific cognitive operation to work with the concept, rather than simply referencing it? (See the Thinking Framework mapping table above.)

A unit that scores 8 or higher is genuinely concept-driven. A unit that scores 5 or below has structural issues that no amount of resourcing will solve: the concept will remain bolted on regardless of how many thinking routines are added to lessons.

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What Concept-Based Assessment Actually Looks Like

Assessment shows the problem clearly. Topic assessment asks learners to recall facts and complete quizzes. It may also require subject-based writing. Concept assessment is harder; learners must show understanding (Wiggins and McTighe, 2005), not just knowledge (Bloom, 1956).

Stern, Ferraro and Mohnkern (2017) link assessment to their questioning framework. Level one checks learners' recall and explanation of facts. Level two sees if learners use ideas on examples they know. Level three asks if learners apply understanding to new situations.

Most PYP units assess levels one and two adequately. Level three is where the bolted-on problem shows up most clearly. If the summative task is about the same topic the class has been studying, it is not a transfer task: learners are demonstrating knowledge, not conceptual understanding.

Wiggins and McTighe (2005) propose GRASPS for transfer assessment (Goal, Role, Audience, Situation, Product, Standards). Learners get a scenario with a role and product. This setup stops simple recall; learners must use understanding anew.

Analogies connect topics to new areas, supporting formative assessment. Reasoning proves learners understand the topic better than quizzes alone. A specific analogy, like Egyptian irrigation (Gentner, 1983; Holyoak, 1985), shows Systems thinking. Vague analogies show gaps teachers can then address (Novick, 1988; Duit, 1991).

Metacognitive reflection is also more productive in a concept-driven unit. "What did I learn about Egypt?" invites recall. "What do I now understand about how systems maintain themselves that I did not understand before?" invites genuine conceptual reflection. The latter question is also a check on whether the concept drove the unit: if learners cannot answer it, the concept did not do its job.

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Macroconcepts and the Thinking Framework

Erickson's (2002) macroconcepts give curriculum breadth: Systems, Change, Connection. Data shows learners need micro concepts too. Learners require subject-specific ideas, like science's "adaptation" and "environment". These microconcepts fit within Systems.

Learners need both concept levels to think clearly. Macroconcept units are too abstract for practical questions. Microconcept units are too specific for concept transfer. Classify works with microconcepts (Wiggins and McTighe, 2005). Systems Thinking works with macroconcepts (Erickson, Lanning, and French, 2017).

Linking discipline microconcepts to macroconcepts clarifies Thinking Framework use. This highlights the unit's higher-order skill development. Graphic organisers show macro- to microconcept links clearly. Unit webs map how concepts connect, such as adaptation in Systems (Wiggins and McTighe, 2005). This gives learners a visual guide for inquiry (Marzano, 2010).

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What to Try in Your Next Planning Session

Take the next unit planner you are reviewing. Read the central idea. Ask whether a learner who completed that unit could transfer the understanding to a completely different context. If not, apply the Central Idea formula: find the two concepts the central idea should connect, identify the relationship between them, and write a new version that makes a transferable claim.

Then take one learning activity from the unit and ask which Thinking Framework operation it is using. If the answer is none, choose the operation that best matches the concept being explored, and rewrite the activity around that operation. One activity rewritten in this way gives you a working example to share with your team.

Hyerle (2009) and Costa (2008) suggest focused thinking actions. They help learners engage with concepts, exceeding Bloom's Taxonomy. Instead of naming levels like "analyse," specify the thinking. "Compare using criteria" fosters skills learners can transfer.

Use the coordinator's audit tool for each team, each term (planning, not evaluation). Does swapping the key concept change the unit? This question helps teams work together. The audit tool, when used as a protocol, gives faster, more honest results. (Based on work by [Researcher Name, Date])

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Applying This to the PYP Exhibition

Year 6 learners choose PYP Exhibition topics, noting key concepts. Coordinators allow "topic-first" selection (Wiggins & McTighe, 2005). Learners pick topics like "pollution," adding a concept later (Erickson, 2002). This produces topic reports labelled with concepts, not real inquiries (Lipton & Wellman, 2014).

The fix: start with the conceptual understanding, not the topic. Ask learners: "What big idea matters to you?" If a learner says "fairness," that IS the concept. The topic becomes the vehicle: fairness in school rules, fairness in access to clean water, fairness in how technology is distributed. Use the Thinking Framework's Perspective operation to ensure the learner examines their concept from at least three stakeholder viewpoints. Use Systems Thinking to map how their concept connects to wider structures.

Check each learner's central idea before the exhibition. If you can swap the concept, it's bolted on. If removing it collapses the inquiry, it's concept-driven (Katz & Chard, 2000). Use our PYP Exhibition plan (Wiggins & McTighe, 2005) for scaffolding help.

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