Successful experience design balances the needs and desires of the user with what is viable for an organisation to deliver.
Tier 1: User experience
The top tier is about your most powerful evidence: data gleaned directly from users, such as through customer research, usability testing or usage metrics.
To evaluate, ask:
- Does the user evidence support our design choices?
- Did our design test well?
- Were users able to achieve their goals easily?
- Are they using your service, product or experience in the way you intended?
Tier 2: User research
If you don’t have direct user evidence, refer back to research and your strategic design principles.
To evaluate and ensure you are staying the course, ask:
- Does the user research support our design choices?
- Do these choices reflect and support our agreed design principles?
- If not, can we make adjustments that will align our design more closely?
- Have we got our design principles right? Do they need to adapt in response to time passing or changed circumstances?
Tier 3: Design theory
If a design decision or recommendation isn’t supported by user evidence or research, look at whether it is supported by theoretical principles.
To evaluate this tier, ask:
- Does this fit with what we know about good design theory (e.g. Fitts’ Law or the psychology of social proof)?
- Why do we think this is a good idea? What is the value of trying it?
- How can we pilot or test it to push our evaluation of it further up the stack
People are often surprised to learn of the scientific foundations that underpin good design. Some can be hard to convince, but there is a lot of very solid theory and research that supports the value of a design-driven approach to problem-solving and improvement.
The order of the tiers in the Validation Stack is important. Always choose a “theoretically inferior” design that tests well with users over a “properly designed” alternative, and only lean on theory for support when you have no other data. User-centred design is about learning and evolving in accordance with user behaviour. Their experience should lead your design practice.
And finally, it’s important to have the strategic strength and cultural courage to throw away a bad design. Many organisations hold onto bad design because of emotional or resource investment, or a set of erroneous beliefs about its value. If your design isn’t supported by user evidence, research, or theoretical principles, throw it away and start fresh.