We know the characteristics of UI being:
- Error Prevention
- Ease of learning
While evaluating our design against these measures, it makes sense making them measurable. So that instead of just saying design is good and it meets client's requirements, designers can have this matrix based on results from usability testing whether these characteristics are met or not.
I want to understand what is the best time to create this criteria and how?
For critical medical service app, 'Error Prevention' criteria should be 'No error' at all.
For complicated software application, (even for advance user), 'Ease of learning' can be 'Consider learnability - Should be able to complete task after going through elearning section which explains how to use particular tool.'
For ticket vendor app, 'Efficiency' should be raising ticket/order in '30 sec'
I have gone through related question Defining “Instantaneous” as part of usability acceptance criteria but I think this discussion is about 'efficiency' only and here I want to understand about other characteristics and also when to create these goals matrics. Should it be at the beginning of the project with the help of Marketing team/stakeholders or just before wireframes creattion; so that wireframes can be molded as per goal.