How do designers make products that fit the human body and are comfortable to use?
Ergonomics and anthropometrics, the use of body measurement data and percentiles, and how designers apply them to make products comfortable, safe and usable.
A focused answer to the WJEC GCSE Design and Technology content on ergonomics and anthropometrics, covering the difference between the two, the use of body measurement data and percentiles, and how designers apply them to make products comfortable, safe and usable.
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What this topic is asking
WJEC's designing principles include ergonomics and anthropometrics, the human side of design. You need to distinguish the two, understand how body measurement data and percentiles are used, and explain how designers apply them to make products fit people. This is core knowledge across all three routes, and it shapes the NEA when you design for a user.
Anthropometrics: measuring the body
Ergonomics: designing to fit
Percentiles and designing for a range
Applying it to products
A designer chooses a dimension from the data depending on the task. For clearance (a doorway, a seat width), design for the largest user (95th percentile) so everyone fits. For reach (a control, a shelf), design for the smallest user (5th percentile) so everyone can reach. For adjustable products such as office chairs and car seats, build in a range so each user sets their own fit.
Try this
Q1. Define anthropometrics. [1 mark]
- Cue. The measurement of the human body.
Q2. State which percentile a designer uses to set the legroom clearance under a desk, and why. [2 marks]
- Cue. The 95th percentile (largest user), so everyone fits.
Exam-style practice questions
Practice questions written in the style of WJEC exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
WJEC-style3 marksExplain the difference between ergonomics and anthropometrics, using a chair as an example.Show worked answer →
A three mark Explain question. Anthropometrics is the measurement of the human body, such as collecting data on seat height, leg length and hip width across a population (1 mark). Ergonomics is the design of products to suit the human body so they are comfortable, safe and efficient to use, using that data (1 mark). For a chair, anthropometric data on leg length sets the seat height, while ergonomics shapes the seat and back so the user sits comfortably with good posture (1 mark). Markers reward the data-versus-design distinction applied to the example. A common error is to treat the two words as synonyms.
WJEC-style4 marksExplain why a designer uses the 5th to 95th percentile range when designing an adjustable office chair.Show worked answer →
A four mark application question on percentiles. Anthropometric data varies across people, so a single fixed size would not fit everyone (1 mark). Designing for the 5th to 95th percentile range means the product suits the middle 90 percent of users, from a small (5th percentile) to a large (95th percentile) person (1 mark). Making the chair adjustable (seat height, back angle) lets each user within that range set it to fit them (1 mark), which is why the very smallest and very largest extremes are usually excluded as uneconomic to design for (1 mark). Markers reward understanding that percentiles cover a range of users and that adjustability handles the spread.
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