Food for thought…
What Most Users Can Do
If you want to target a broad consumer audience, it’s safest to assume that users’ skills are those specified for level 1. (But, remember that 14% of adults have even poorer skills, even disregarding the many who can’t use a computer at all.)
To recap, level 1 skills are:
* Little or no navigation required to access the information or commands required to solve the problem
* Few steps and a minimal number of operators
* Problem resolution requiring the respondent to apply explicit criteria only (no implicit criteria)
* Few monitoring demands (e.g., having to check one’s progress toward the goal)
* Identifying content and operators done through simple match (no transformation or inferences needed)
* No need to contrast or integrate information
Anything more complicated, and your design can only be used by people with skills at level 2 or 3, meaning that you’re down to serving 31% of the population in the United States, 35% in Japan and the UK, 37% in Canada and Singapore, and 38% in Northern Europe and Australia. Again, the international variations don’t matter much relative to the big-picture conclusion: keep it extremely simple, or two thirds of the population can’t use your design.