Key Idea: Inclusive design = one product that works for as many people as possible, with no special version. Three kinds of difference: physical, sensory, cognitive. The 50th percentile is the middle of ONE dimension. Nobody is average in several at once, so the band collapses as requirements stack. Design for extremes: reach, force and readability from the least capable user; clearance and capacity from the largest. Where inclusion is impossible, state the exclusion and offer an alternative.
Paper 1 — multiple choice
- Match a barrier to physical, sensory or cognitive
- Say what the 50th percentile actually describes
- Pick which extreme a requirement comes from
- Identify a product designed for extremes
Paper 2 — analysing a product
- Evaluate a named product's inclusivity across the three kinds
- Explain why designing for the average fails
- Apply a design-for-extremes strategy to a product
- Evaluate a case where exclusion is deliberate
Carried into the design project
- Criterion A — the user group you chose, and who it leaves out
- Criterion B — anthropometric criteria taken from the right extreme
- Any exclusion must be stated, not discovered by a marker
This single table answers more C1.2 marks than anything else. The test is whether the requirement lets somebody IN or lets something THROUGH.
| Requirement | From which user | Why |
|---|---|---|
| Reach — shelf, control, emergency stop | The smallest | Anybody taller can still reach down |
| Force — door, catch, lid, trigger | The weakest | A light control inconveniences nobody |
| Readability and comprehension | The least capable served | Clearer text and simpler steps help everybody |
| Clearance — doorways, gaps, legroom | The largest | Smaller users pass through easily |
| Headroom and capacity | The largest or heaviest | Under-sizing fails at the busiest moment |
Design at the edge and the middle comes free. Dropped kerbs were built for wheelchairs and are used by every pram and suitcase. Subtitles were for deaf viewers and are watched by about a third of all viewers.
The distribution, the collapse of the average band, and four cases where an extreme user improved the product for everybody.
🔒 Interactive diagram
Explore the labelled diagram, charts and maps for this topic in study mode.
| Barrier on a ticket machine | The change | Who else it helps | |
|---|---|---|---|
| Physical | Coin slot needs a pinch grip, at standing height | Card reader at seated height, usable with a closed fist | Anyone holding a child, carrying bags, wearing gloves |
| Sensory | A quiet beep and a pale tick on a white screen | High contrast, plus sound AND a visible change | Everybody in a noisy station or in bright sun |
| Cognitive | Six options, a timeout, an error in jargon | One instruction per screen, no timeout, plain words, undo | Every first-time or anxious user, and second-language users |
Important: "It considers everyone." Name the barrier, the change, and who else it helps. Saying the average is inaccurate. It is perfectly accurate — the fault is that nobody is average in several dimensions at once. Taking every requirement from the same extreme. Clearance from the smallest excludes large users just as surely.
Permanent, temporary and situational — three users with the same need, and only one of them in a statistic.
🔒 Interactive diagram
Explore the labelled diagram, charts and maps for this topic in study mode.
Evaluate the inclusivity of a supermarket self-service checkout, covering physical, sensory and cognitive differences, and give one change for each.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
A manufacturer designs a garden fork for the 50th-percentile adult. Explain why this is likely to fail, and what should be done instead.
🔒 Model answer plan
See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.
What question replaces "is this inclusive?"
Why must important feedback use two channels?
What are permanent, temporary and situational impairments?
How do you tell which extreme a requirement comes from?
When is designing for the average defensible?
What do you do when inclusion is impossible?
Exam tips
- Name the barrier, the change, and who else it helps.
- Cover all three: physical, sensory, cognitive.
- Anything important needs two channels.
- Access from the least capable; space and capacity from the largest.
- The average is accurate — the fault is combining dimensions.
- If exclusion is unavoidable, state it and offer an alternative.