What competing factors must a designer balance to make a product that works, sells and can be made?
The design factors a product must satisfy: function and performance, aesthetics, ergonomics and anthropometrics, the market, economics and cost, ease of manufacture, durability and safety, and how they are balanced and prioritised.
An SQA Higher Design and Manufacture answer on the design factors a product must satisfy, covering function and performance, aesthetics, ergonomics and anthropometrics, market, economics, ease of manufacture, durability and safety, and how a designer balances and prioritises them for a viable commercial product.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this key area is asking
The SQA wants you to know the design factors that every product has to satisfy, to explain how each one shapes design decisions, and to show that a designer balances and prioritises them rather than maximising any single one. This is one of the most heavily examined topics in the question paper: items ask you to explain how a named factor (often ergonomics, aesthetics or cost) influences the design of a given product, usually for 4 to 6 marks.
The design factors
- Function and performance
- The product must do its job, and do it well. Function is the core purpose (a kettle boils water); performance is how well it does it (how fast it boils, how little energy it uses). These are usually the first factors a specification fixes.
- Aesthetics
- How the product looks and feels: its form, proportion, colour, texture and finish. Aesthetics must suit the target market - a children's toy, a kitchen appliance and a luxury watch follow very different visual rules. Good aesthetics help a product sell against competitors.
- Ergonomics and anthropometrics
- Ergonomics is fitting the product to the user so it is comfortable, safe and easy to use; anthropometrics is the body-measurement data (heights, reaches, grip sizes) that ergonomics relies on. Designers use percentile data, usually designing for the 5th to 95th percentile, so the product suits the great majority of users.
- The market
- The product must suit its target users and the price point they will pay. Market research identifies who the users are, what they want and what competitors offer, and the design is shaped to fit.
- Economics and cost
- The product must be cheap enough to make and to buy. Cost covers materials, manufacture, labour, packaging and transport. Cost limits the choice of materials and processes and is one of the strongest constraints on most designs.
- Ease of manufacture
- The product must be makeable with the available processes at the planned scale of production. Designing for manufacture means choosing forms, materials and joints that suit the chosen process and avoid waste or difficulty.
- Durability and safety
- The product must last for its expected life and must be safe to use, meeting relevant standards. Safety can never be traded away, even when other factors are squeezed.
Ergonomics and anthropometrics in detail
For a handheld product the designer uses hand-width and grip data to size the handle, places controls within finger reach so the user does not change grip, and shapes the form to spread pressure and reduce strain over long use. For seating the designer uses seat-height, depth and back-support data so the user is supported without pressure points. The aim is always to suit the spread of real users, not one average person.
Balancing and prioritising the factors
The factors pull against each other, so a designer cannot maximise them all:
- A premium material improves performance and aesthetics but raises cost and can make manufacture harder.
- A complex shape that looks striking may be expensive to mould and slow to make.
- Heavier, thicker materials improve durability but worsen ergonomics (weight) and cost.
The designer therefore prioritises the factors that matter most for the product and its market, guided by the specification. For a budget kettle, low cost and ease of manufacture come first; for a luxury kettle, aesthetics and perceived quality lead. The right balance is the one that makes the product viable for its users at its price.
Where this fits in the course
Design factors run through the whole Design area and the design assignment, where your specification and evaluation should be organised around them. In the question paper, "explain how factor X influences product Y" items are among the most common, so practise turning each factor into specific design decisions for a named product.
Try this
Q1. Explain how aesthetics and the market influence the design of a luxury watch. [4 marks]
- Cue. Aesthetics: form, finish and materials signal quality. Market: the design targets buyers who pay for status and craftsmanship.
Q2. Explain how anthropometric data is used in the design of an office chair. [4 marks]
- Cue. Seat-height, depth and back-support data sized to the 5th to 95th percentile so the chair supports short and tall users comfortably.
Q3. Explain why cost and ease of manufacture limit a designer's choice of materials. [3 marks]
- Cue. Materials must be affordable at the planned scale and suit the chosen process; an expensive or hard-to-process material can make the product unviable.
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 Higher6 marksExplain how ergonomics and anthropometrics influence the design of a product such as a power drill.Show worked answer →
Worth about 6 marks, so the marker wants three or four developed points,
each linking a factor to a design decision. The mark scheme rewards
ergonomic and anthropometric reasoning applied to the product, not
definitions alone.
Grip size from anthropometric data. The designer uses percentile hand
data so the handle fits the range of users, typically designing the grip
circumference for the 5th to 95th percentile so both small and large
hands can hold it comfortably without strain.
Reach and control placement. The trigger and speed control are placed
within easy reach of the index finger so the user does not have to shift
grip, reducing fatigue during repeated use.
Comfort and reduced strain. A soft over-moulded grip spreads pressure and
damps vibration, lowering the risk of injury when the drill is used for
long periods, which is an ergonomic benefit.
Weight and balance. Anthropometric and ergonomic thinking puts the centre
of mass over the grip so the drill does not twist in the hand, improving
control. A top answer states explicitly that fitting the product to the
user makes it safer, more comfortable and easier to control.
SQA Higher4 marksExplain why a designer must balance competing design factors rather than maximise one.Show worked answer →
Worth about 4 marks. The markers want the idea of trade-offs with
examples, not a list of factors.
Factors pull against each other. Improving one factor often worsens
another, for example using a premium material improves performance and
aesthetics but raises cost and may make manufacture harder, so the
designer cannot simply maximise everything.
The product must be viable. A commercially viable product has to function,
appeal to its market, be safe, and be made at a price people will pay, so
the designer prioritises the factors that matter most for that product and
its users.
Worked example. For a budget kettle, low cost and ease of manufacture are
prioritised over premium aesthetics; for a luxury kettle the priorities
reverse. A strong answer states that balancing factors against the
specification is what makes a design fit for purpose.
Related dot points
- The design process and the iterative design, make and test cycle: the brief, research, specification, idea generation, development, prototyping, evaluation and the feedback loops that link them.
An SQA Higher Design and Manufacture answer on the design process and the iterative design, make and test cycle, covering the brief, research, specification, idea generation, development, prototyping and evaluation, and why the stages feed back into each other rather than running in a straight line.
- Graphic techniques and modelling used through the design process: freehand sketching, pictorial and orthographic working drawings, CAD, and physical models and prototypes, and the role of each in generating, developing, testing and communicating a design.
An SQA Higher Design and Manufacture answer on the graphic techniques and modelling used through the design process, covering freehand sketching, pictorial and orthographic working drawings, CAD, and physical models and prototypes, and when each is used to generate, develop, test and communicate a design.
- Evaluation techniques used through the design process: evaluating ideas and products against the specification, user trialling and testing, comparison and selection methods, and using the results to refine the design.
An SQA Higher Design and Manufacture answer on evaluation techniques, covering how a designer judges ideas and products against the specification, uses user trialling and testing, compares and selects ideas objectively, and feeds the results back to refine the design.
- The impact of design and manufacturing technologies on society, the environment and the workforce: sustainability and the six Rs, resource use and waste, planned obsolescence, and the effects of automation and global manufacture on workers.
An SQA Higher Design and Manufacture answer on the impact of design and manufacturing technologies on society, the environment and the workforce, covering sustainability and the six Rs, resource use and waste, planned obsolescence, and the effects of automation and global manufacture on workers.