What is the difference between primary and secondary research?

Primary research is information the designer gathers first-hand for this project, such as interviews, observation, surveys and testing a product yourself. Secondary research is information gathered by others that already exists, such as books, websites, datasheets and existing product reviews. A strong investigation uses both: secondary research gives quick background, and primary research gives evidence specific to your actual users.

What are anthropometrics and ergonomics, and how do they differ?

Anthropometrics is the study of human body measurements, such as hand span, reach height and grip strength. Ergonomics is the wider study of designing products so they fit the human body and are comfortable, safe and efficient to use. Anthropometric data is one of the main inputs to ergonomic design: you use body measurements to size a product so it suits its intended users.

What is a percentile in anthropometric design?

A percentile tells you the proportion of people a measurement covers. The 5th percentile value is exceeded by 95 percent of people, and the 95th percentile value is exceeded by only 5 percent. Designers commonly size a product to fit from the 5th to the 95th percentile, which suits about 90 percent of users, choosing which percentile to design for depending on whether reach, clearance or strength is critical.

How do research findings become a design specification?

Each finding is turned into a clear, measurable requirement that the solution must meet, and the requirement is justified by the research that produced it. For example, a measured 95th percentile grip width becomes a specification point on handle size. A good specification covers function, ergonomics, materials, safety, cost and aesthetics, with figures wherever possible so the product can be tested against it.

SingaporeDesign and Technology

Research and Investigation: how Singapore O-Level Design and Technology designers gather primary and secondary evidence, apply anthropometrics and ergonomics, analyse products and write a justified specification

Q: What is product analysis and why is it useful?

Product analysis is examining an existing product to learn how it works, what it is made from, how it is constructed, and how well it serves the user. You look at function, materials, construction, ergonomics, aesthetics and cost. It is useful because it reveals good features to keep and weaknesses to improve, giving evidence that feeds straight into a new and better design.

A Singapore O-Level Design and Technology (SEAB 7059) module overview of research and investigation. Primary versus secondary research, anthropometrics and ergonomics with percentiles, product analysis, and turning findings into a justified, measurable design specification, with links to every dot point.

Generated by Claude Opus 4.87 min readSEAB-7059Updated 2026-06-13

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What this module covers
Gathering the right evidence
Fitting the product to the human body
Learning from existing products
Turning evidence into targets
How this module is examined
Check your knowledge

What this module covers

Research and Investigation is where a design stops being guesswork and starts being grounded in evidence. In O-Level Design and Technology (SEAB 7059), the marks at this stage come from gathering relevant information, applying it to real users, and converting it into a measurable specification. In the Design Project, this is the section that turns a given situation into clear targets to design toward; in the written paper, it appears as questions on research methods, anthropometrics, ergonomics and specification writing. This overview links the four dot points and shows how they connect.

See the full set of dot points for this module under /sg-o-level/design-and-technology/syllabus/research-and-investigation.

Gathering the right evidence

The starting point is choosing methods that actually answer your questions. The primary and secondary research dot point distinguishes first-hand methods (interviews, observation, surveys, your own product testing) from existing sources (books, websites, datasheets). Secondary research gives quick background; primary research gives evidence specific to your users. The mark, though, is in turning findings into design requirements, not in collecting information for its own sake.

Fitting the product to the human body

Products must suit the people who use them, which is where anthropometrics and ergonomics comes in. Anthropometrics is body-measurement data; ergonomics is the wider science of designing for comfort, safety and efficiency. The key technique is the percentile: design from the 5th to the 95th percentile to suit about 90 percent of users, choosing the right percentile depending on whether reach, clearance or strength is the critical factor.

Learning from existing products

You do not design in a vacuum. Product analysis examines an existing product by function, materials, construction, ergonomics, aesthetics and cost, revealing features worth keeping and weaknesses worth improving. This is secondary-style evidence with a sharp purpose: every observation should suggest a requirement for your new and better design.

Turning evidence into targets

All the research converges on one output: a specification. Writing a design specification shows how to build justified, measurable points across function, ergonomics, materials, safety, cost and aesthetics, each traceable to a research finding. A specification with figures can be tested; one full of vague aims cannot, and that distinction is where marks are won and lost.

Using percentiles to size a handle

Survey data gives the hand-grip diameter that users can comfortably close around. The 5th percentile is 95 mm and the 95th percentile is 115 mm. Decide the handle circumference range.

Step 1: Identify the critical dimension

The critical dimension is grip diameter, because a handle too thick for small hands cannot be gripped safely. To include nearly everyone, design across the 5th to 95th percentile range.

Step 2: Read off the percentile values

5th percentile comfortable grip = 95 mm. 95th percentile = 115 mm. Designing within this band suits about 90 percent of the target users.

Step 3: Convert to a circumference if needed

If the data is given as the circumference a hand can close around, the handle's outer circumference should fall between roughly 95 mm and 115 mm. Treating the handle as a cylinder, circumference $C = \pi d$ , so the diameter range is about $d = \tfrac{95}{\pi} \approx 30\ \text{mm}$ to $d = \tfrac{115}{\pi} \approx 37\ \text{mm}$ .

Step 4: Write the specification point

"The handle circumference must be between 95 mm and 115 mm (diameter about 30 mm to 37 mm), to suit the 5th to 95th percentile grip of the target users." This is justified and testable.

How this module is examined

Choose and justify methods. Match primary or secondary research to the question, and explain why each method suits the problem.
Apply percentiles correctly. Know what 5th and 95th percentile mean and design across the right range for reach, clearance or strength.
Analyse products purposefully. Turn each observation about an existing product into a requirement for a better design.
Write measurable, justified specification points. Cover function, ergonomics, materials, safety, cost and aesthetics, with figures and a research reason for each.

Check your knowledge

Short and calculation questions across the module. Attempt them, then check the worked solutions.

State the difference between primary and secondary research, giving one example of each. (2 marks)
State the difference between anthropometrics and ergonomics. (2 marks)
Explain what the 5th to 95th percentile range means and roughly what proportion of users it suits. (2 marks)
A handle is to be sized so its circumference matches a grip diameter of $30\ \text{mm}$ . Treating the handle as a cylinder, calculate the circumference. Use $\pi = 3.14$ . (2 marks)
Turn this finding into a measurable specification point: "users with small hands could not grip the thick handle". (1 mark)

Sources & how we know this

Singapore-Cambridge GCE O-Level Design and Technology (Syllabus 7059) — Singapore Examinations and Assessment Board (2026)