1. Usage Profiles

2. Usage profiles never-ending 4 Process of “knowing the user” is never-ending much 4 So much to discover (social background, organisational character, culture, age, education, sex etc.) changing 4 Users keep changing 4 “ Every step...in recognizing them as individuals whose outlok is different from the designer’s is likely to be a step closer to successful design” (Shneiderman p.66)

3. Novice users 4 “first user” community - no syntactic computer knowledge using the machine) and probably less semantic knowledge of computer systems in general. 4 distinguish between first-time users (may have high task knowledge) and novices - though both may suffer “technophobia” 4 overcoming these limitations is a serious challenge to the designer

4. Novice users - design implications 4 Restrict interaction vocabulary to small number of constantly used terms 4 Permit novice to carry out a few simple tasks easily to build confidence 4 Informative feedback on each task is helpful 4 Provide specific error messages 4 Minimise burden of “computer” concepts and jargon 4 Maximise help (user manuals, on line help etc.)

5. Knowledgable intermittent users semantic 4 Maintain semantic knowledge of both task and computers syntactic 4 Unable to maintain syntactic knowledge of system (i.e. how to access, manipulate it) relaxed exploration 4 Protection from danger of failure necessary for relaxed exploration of features

6. Knowledgable intermittent users - design implications 4 Lighten burden of memory with simple and consistent structure in command language, menus, terminology etc. recognition 4 Emphasize “recognition” over “recall” consistent sequences 4 Provide consistent sequences of actions to assure users they are accomplishing tasks online help 4 Provide online help screens, and well-organised reference manuals

7. Expert frequent users 4 A.k.a. “power” users 4 Thoroughly familar with semantic and syntactic aspects of system 4 Seek rapid completion of tasks 4 Design implications same as for Computer Experts

8. Multiple usage classes 4 Designing for one class of users is easy; satisfying several is hard multiple classes 4 When designing for multiple classes use a layered approach to learning: –teach novices a minimal subset of objects and actions; expose experts to wide range, rapid feedback progress through “layers –then progress through “layers” of expertise task –design of layers should be governed by progress through task semantics user control –consider providing user control of layering