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IBMYP Interdisciplinary Unit (IDU): The Complete Guide
Everything students and parents need to know about the MYP Interdisciplinary Unit — what it is, how the four assessment criteria work, real IDU project examples, and how to prepare for the interdisciplinary eAssessment.
If your child has come home talking about a project that combines Maths and Geography, or History and Science, and you’re wondering how on earth that gets graded, you’ve encountered the MYP Interdisciplinary Unit — usually shortened to ‘IDU.’ Unlike a single-subject assessment, the IDU deliberately asks students to genuinely connect two or more subject groups to explore an issue that no single discipline could fully explain on its own. It’s one of the more distinctive and, for many students and parents, more confusing parts of the MYP framework, largely because it is assessed using its own dedicated set of criteria rather than the criteria used in any single subject.
This guide explains exactly what the IDU is, how the four interdisciplinary assessment criteria work, what makes a genuinely strong (rather than superficially ‘combined’) IDU project, real example topics across subject pairings, how the IDU connects to the MYP 5 eAssessment, and the specific coaching approach PrepSeven uses to help students plan and execute a high-scoring interdisciplinary unit.
What Is an Interdisciplinary Unit (IDU)?
An Interdisciplinary Unit is a unit of study, usually undertaken in the later years of MYP, that requires students to draw on and genuinely combine understanding from at least two different subject groups to investigate a single issue, question, or problem. The defining feature of an IDU — and the thing that most distinguishes it from a project that simply happens to touch on two subjects — is that it must produce a new, combined understanding that neither subject could produce on its own. A unit that studies a topic in Geography and then, separately, in Mathematics is multidisciplinary, not interdisciplinary; a genuine IDU asks students to actively synthesise concepts, methods, or perspectives from both disciplines into a single coherent piece of understanding.
For students completing the IB MYP Certificate, one of the eight required eAssessments in MYP 5 is specifically an interdisciplinary assessment, which draws directly on the skills developed through IDUs completed earlier in the programme. This is why understanding and practising genuine interdisciplinary thinking well before MYP 5 pays off directly at exam time.
The Four IDU Assessment Criteria Explained
Interdisciplinary units are not graded using the criteria of either individual subject involved. Instead, IB has a distinct, subject-group-neutral set of four criteria specifically for interdisciplinary understanding, each scored out of 8.
The most common reason strong students underperform on IDU tasks is treating Criterion B as optional or automatic. Genuine synthesis has to be demonstrated explicitly — a project that presents a Science section and then a separate Geography section, without ever combining them into one integrated argument or product, will lose significant marks on Criterion B even if both sections are individually excellent.
What Makes a Genuinely Strong IDU (Not Just Two Subjects Side by Side)
The single biggest pitfall in IDU work is producing what looks like two separate single-subject projects stapled together. A genuinely strong interdisciplinary unit identifies a real conceptual bridge between the disciplines from the very start.
A Reliable Process for Planning a Genuine IDU
- Choose an issue or question that neither subject alone can fully answer (e.g. ‘Why do coastal cities struggle to plan for rising sea levels?’ genuinely needs both Geography and Science/Physics, not just one).
- Identify the specific concept or method each subject contributes (e.g. Geography’s understanding of human settlement patterns; Physics’ understanding of thermal expansion and ice melt).
- Explicitly plan the point of synthesis before starting research — what new understanding will emerge only once both perspectives are combined?
- Research and develop each disciplinary strand with genuine depth (this is Criterion A) before attempting to merge them.
- Build the combined product, argument, or model that could not exist using only one subject’s tools or perspective (this is Criterion B).
- Structure the final communication so the interdisciplinary link is stated explicitly, not left implicit (Criterion C).
- Reflect specifically on what was gained, and what the limits of a single-subject approach would have been (Criterion D).
Example IDU Topics by Subject Pairing
The strongest IDU topics start from a real-world issue and work backward to identify which two disciplines genuinely illuminate it, rather than starting with two subjects and searching for a forced connection.
- Mathematics + Geography: modelling population growth and urban sprawl using statistical projections and settlement pattern analysis.
- History + Science: examining how a historical pandemic’s spread can be explained through both social/political conditions and epidemiological science.
- Design + Physical and Health Education: engineering sports equipment, combining design-cycle methodology with biomechanics and injury-prevention principles.
- Economics + Environmental Science: analysing the true cost of a local environmental policy by combining economic cost-benefit analysis with ecological impact data.
- Language and Literature + Visual Arts: exploring how a historical or social movement is represented differently through written texts and visual propaganda or art.
- Global Politics + Geography: examining a resource conflict (water, minerals, land) through both the geographic distribution of the resource and the political structures governing its control.
How the IDU Connects to the MYP 5 eAssessment
Students completing the IB MYP Certificate sit an on-screen interdisciplinary eAssessment as one of the eight required assessments in MYP 5. This exam presents an unfamiliar real-world scenario and requires students to apply genuine interdisciplinary thinking — identifying which subjects are relevant, drawing on disciplinary knowledge, and synthesising a combined response — under timed conditions.
Because the eAssessment uses unfamiliar scenarios rather than a pre-planned classroom project, students who have only ever completed heavily scaffolded, teacher-designed IDUs sometimes struggle when asked to independently identify the relevant disciplinary connections themselves. Regular practice identifying genuine interdisciplinary links across a range of real-world issues — not just the specific topics covered in class — is the most effective preparation.
Study Strategies by Year Group
MYP 1-3: Building the Habit of Making Connections
- Practise noticing when a topic studied in one subject connects to something learned in another, even informally.
- Keep a simple ‘connections journal’ noting any moment a concept from one class reminded you of another subject.
MYP 4: Preparing for Formal IDU Work
- Practise stating, in one sentence, what each subject contributes to a chosen issue before starting research.
- Get comfortable using vocabulary from two different subjects accurately within the same piece of writing.
MYP 5: IDU Projects and eAssessment Readiness
- Practise identifying genuine interdisciplinary links in unfamiliar real-world scenarios, not just pre-assigned class topics.
- Build a personal checklist covering all four criteria (A-D) to review before submitting any IDU work.
- Complete timed practice scenarios that mirror the on-screen eAssessment format in the term leading up to the exam window.
Common Mistakes That Hold Students Back
How PrepSeven Supports MYP Interdisciplinary Unit Students
PrepSeven’s tutors are certified or former IB examiners who understand exactly how the four interdisciplinary criteria are applied in practice. We help students choose genuinely interdisciplinary topics rather than forced pairings, build strong disciplinary grounding in each contributing subject, structure a clear and explicit synthesis, and prepare specifically for the MYP 5 interdisciplinary eAssessment using realistic, unfamiliar-scenario practice.
Frequently Asked Questions
Q1. What is the difference between interdisciplinary and multidisciplinary work?
Multidisciplinary work studies a topic through multiple subjects separately, without combining them; a genuine interdisciplinary unit synthesises concepts or methods from each subject into one new, combined understanding or product.
Q2. How many subjects need to be involved in an IDU?
At least two subject groups must be genuinely and substantively combined, though some units may draw on more than two as long as each contributes meaningfully to the synthesis.
Q3. Is the IDU graded using the criteria from each individual subject?
No. The IDU uses its own distinct set of four criteria — Disciplinary Grounding, Synthesizing, Communicating, and Reflecting — that apply regardless of which two subjects are involved.
Q4. Do all MYP students complete an interdisciplinary eAssessment?
The on-screen interdisciplinary eAssessment is one of the eight required assessments only for students pursuing the official IB MYP Certificate in MYP 5; other students typically complete IDU project work assessed internally by their school.
Q5. How is the IDU different from the MYP Personal Project?
The Personal Project is an independent, self-directed exploration of a personal interest assessed on planning, applying skills, and reflecting; the IDU specifically requires combining two or more academic subject groups and is assessed on disciplinary grounding, synthesis, communication, and reflection.
Q6. What's the most common reason students lose marks on an IDU?
By far the most common issue is presenting two subjects side by side without a genuine, explicitly stated point of synthesis — this caps marks on both Criterion B (Synthesizing) and Criterion C (Communicating).
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