What are the design factors, and how does each one influence the design of a product?
The design factors that influence the design of a product: function, performance, aesthetics, ergonomics (anthropometrics, physiology and psychology), market and consumer demands, economic factors, environmental factors and safety, and the tensions and trade-offs between them.
A focused answer to the SQA National 5 Design and Manufacture content on design factors, covering function, performance, aesthetics, ergonomics (anthropometrics, physiology, psychology), market, economic, environmental and safety factors, and the trade-offs designers make between them.
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What this dot point is asking
The SQA wants you to know the design factors that shape every product and, crucially, to explain how each one influences a design. The most common exam fault is naming a factor without saying what effect it has, so every point below is framed as a cause and an effect. You also need to understand that the factors pull against each other, so designers make trade-offs.
Function and performance
Function comes first: a product that does not work has failed, however attractive it is. Performance separates a basic product from a good one, and is tested against the specification through the design/make/test cycle.
Aesthetics
Aesthetics is how the product appeals to the senses, mainly sight but also touch and sound. It covers the shape, form, colour, texture, pattern and proportion of the product. Good aesthetics attract buyers and signal quality, which is why two products with the same function can sell at very different prices. Designers use the elements and principles of design (line, shape, colour, texture; balance, contrast, proportion, harmony) to control the look.
Ergonomics
Ergonomics is the study of how a product fits the human user. The SQA splits it into three parts.
A product that ignores ergonomics is uncomfortable, tiring or confusing to use, even if it works.
Market, economic, environmental and safety factors
- Market and consumer demands
- The product must meet what the target market wants in terms of style, features and price. Market research finds out these demands so the design matches buyers' expectations and trends.
- Economic factors
- The cost of materials, labour and manufacturing must allow the product to be made at a profit and sold at a price the market will accept. Cheaper materials or simpler manufacture cut cost but may reduce quality.
- Environmental factors
- The choice of materials, the energy used to make and run the product, and how it is disposed of or recycled all matter. Designers reduce harm by choosing recyclable or renewable materials and reducing waste (linked to the life cycle and the 6 Rs).
- Safety
- The product must not harm the user in normal use: no sharp edges, stable construction, non-toxic materials, and compliance with safety standards. Safety is often a legal requirement, not an option.
The tensions between factors
This is the key National 5 idea: factors conflict, so the best design is a balanced compromise for the given brief, not a maximum on every factor at once.
Try this
Q1. State what is meant by the function of a product. [1 mark]
- Cue. The main purpose or job the product is designed to do.
Q2. Describe two ways environmental factors could influence the design of a drinks bottle. [2 marks]
- Cue. Use a recyclable plastic; reduce material to cut waste; design for refilling and reuse.
Q3. Explain why a designer must compromise between design factors. [2 marks]
- Cue. Factors conflict, for example improving performance or safety raises cost, so the best design balances them for the brief rather than maximising any single one.
Exam-style practice questions
Practice questions written in the style of SQA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
SQA-style Explain4 marksA company is designing a new electric kettle. Explain how two different design factors would influence its design.Show worked answer →
Award up to 2 marks for each factor that is explained as a cause and an effect, to a maximum of 4. Function: the kettle must boil water safely and quickly, so the designer must include a heating element of the correct power rating and an automatic cut-off, otherwise the product would not do its main job (2). Ergonomics: the handle must fit the range of hand sizes of users and stay cool to touch, so the designer uses anthropometric data and a heat-resistant plastic, which makes the kettle comfortable and safe to lift and pour (2). Other creditable factors include aesthetics (a modern shape and colour to attract buyers), safety (a stable base and concealed element), economic (keeping material and manufacturing costs low so the selling price is competitive) and environmental (recyclable materials). Markers reward the link between the factor and its effect on the design, not a bare definition.
SQA-style Describe3 marksDescribe how ergonomics would be considered when designing a hand-held games controller.Show worked answer →
Award 1 mark per developed point, up to 3. Anthropometrics: the controller is sized using data on hand and finger dimensions so it fits the target users comfortably (1). Physiology: the buttons and triggers are positioned so the thumbs and fingers can reach them without strain during long use, reducing fatigue (1). Psychology: clear, well-grouped controls and familiar layouts make the controller easy to understand and use without confusion (1). A further valid point is the use of textured grips so the controller is not dropped (1). Markers reward points that show ergonomics being applied to the product, not a general definition of the word.
Related dot points
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