Constraints and Considerations

What is a Constraint?

A constraint is an aspect of the problem outlined in the design brief that CANNOT be changed. They are ‘set in concrete’

Constraints are typically (but not always) well defined. Typical constraints could be;

  • ECONOMICS (time and budget)
  • USER-CENTRED DESIGN (catering for a specific end-user)
  • PURPOSE, FUNCTION & CONTEXT (what the product needs to do)

What is a Consideration?

Considerations are aspects of the design brief that must be considered but are PREFERRED, but not mandatory

A good example of considerations is;

  • VISUAL, TACTILE & AESTHETIC FACTORS (style, look, feel)
  • TECHNOLOGIES (in production and in the product)

A Note on Constraints and Considerations

These are not always black and white. For instance what one person thinks is a constraint and some may think is a consideration

A good example on the difference between constraints and considerations is around something like size

It is not always necessarily a constraint, like we might think without seeing the detail

If in a design brief it said something like;

“It must be small”

How big is small? Small is a relative term. A small elephant is still larger than a large ant

But if the design brief said…

“It must be small enough to fit into the space next to my bed. 600 x 600 x 600mm”

That would be a constraint. A solution any larger than this would not work for the person commissioning the work.

Writing your Constraints and Considerations

When you have decided on your constraints and considerations, they need to be written in a particular way. Here is the format

  1. Identify the Product Design Factor that is relevant. Put that in CAPITAL LETTERS at the start of your constraint or consideration
  2. Identify the constraint or consideration with these ‘intros’
    • For a constraint, use the word must – ‘The solution must have…’ or ‘It must be’
    • For a consideration, use the word may – ‘The solution may…’ or ‘It may…’

Examples of constraints:

  • ECONOMICS – The solution must be made for the end-users budget of $200 or less
  • VISUAL, TACTILE & AESTHETIC FACTORS – The solution must be in the art deco style to fit in with the building
  • LEGAL RESPONSIBILITIES- The solution must be safe enough for children 3 years old and above
  • USER-CENTRED DESIGN – It must be easy for the end-user to pick up the final solution and use, as the solution is open to the general public
  • PURPOSE, FUNCTION & CONTEXT – The solution must have the primary function of de-pipping an avocado

Examples of considerations

  • INNOVATION AND CREATIVITY – The solution may be made using emerging technologies
  • MATERIALS – It may be made out of a variety of suitable materials
  • TECHNOLOGIES – The solution may be constructed from a variety of tools, equipment, and machines
  • SUSTAINABILITY – The solution may be made from recycled and reused materials and with sustainable processes and practices

The second last word on Constraints and Considerations

They are important. Don’t simply put something together and forget about it. These constraints carry through all the way through to evaluation. You research depends on them, your deciding on a design option depends on them, and your evaluation of the product depends on them. And your end-users experience as well.


  • Budget
  • Size
  • Aesthetics / Appearance
  • Time
  • Quality
  • Materials
  • Function (primary and secondary)
  • Finish of product
  • Special user requirements
  • Social concerns
  • Safety
  • Ergonomics
  • Environmental issues
  • Storage