Human-Computer Interaction & web design
Shneiderman's "Eight Golden Rules of Interface Design"
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| Shneiderman's "Eight Golden Rules of Interface Design" Golden rules and heuristics ■ Use both knowledge in the world and knowledge in the head - people learn better when the information needed to complete a task is readily available to them. Text should be kept to a minimum and the language used should be clear and concise. Alerts and prompts will guide users through the system. ■ Simplify the structure of tasks- Try minimizing the amount of irrelevant information or reducing the number of choices. Use features like tooltips, undo and history to aid memory. ■ Make things visible - Feedback is critical to this principle, always give good feedback to the user about the state of the system and make the outcomes of their actions as obvious as possible. ■ Get the mappings right- Mapping is the relationship between a control, whatever it effects and the resulting action of the control. Take the common electric light switch, it’s an example of particularly bad mapping. ■ Exploit the power of constraints- Constraints prevent errors from occurring by taking the control out of the hands of users. For example, if an application requires an email registration in order for people to use it then ask the user to fill in their email address twice and make sure both are being validated as actual email addresses. ■ Design for error- Assume that every error that could be made will be made, test for it and provide contingencies when it happens. Take the time to think carefully about your error messages, try to describe what’s happened in as few words as possible and make sure the user can recover from the error. ■ When all else fails, standardize- This can be rephrased as ‘don’t reinvent the wheel. If there isn’t a quicker, easier or simpler way to carryout a task then tap into the learned knowledge and behaviors the user has already acquired. Norman’s Seven Principles DESIGN EVALUATION What is evaluation Evaluation is the process to asses and test the system to ensure they actually behave predictably, as expected and meet user requirements It is not a single phase in the design process. Evaluation should occur throughout the design life cycle Feedback of evaluation should lead the design modification. Goals of evaluation To assess the extent and accessibility of the system’s functionality. - Must meet user’s expectations - Allow users to perform task easily To assess user’s experience of the interaction. - How easy to lean the systems? - Work load to be diverted to the system not the users To identify any specific problems with the system. - Eliminate confusion - Handling errors Cognitive Walkthrough ■ The cognitive walkthrough is a usability evaluation method in which one or more evaluators work through a series of tasks and ask a set of questions from the perspective of the user. ■ The focus of the cognitive walkthrough is on understanding the system’s learnability of new or infrequent users. It is a task specific approach to usability. Findable Accessible Usable Desirable Valuable Credible Users Experience UX) Cognitive Walkthrough ■ A specification or prototype of the system. It doesn’t have to be complete, but it should be fairly detailed. Details such as the location and wording fora menu can make a big difference. A description of the task the user is to perform on the system. This should be a representative task that most users will want to do. A complete, written list of the actions needed to complete the task with the proposed system. An indication of who the users are and what kind of experience and knowledge the evaluators can assume about them. How do we evaluate What do we need ▪ Is the effect of the action the same as the user’s goal at that point? ▪ Will users see that the action is available? ▪ Once users have found the correct action, will they know it is the one they need? ▪ After the action is taken, will users understand the feedback they get? |