Evaluating user interface is becoming an important skill.  At some point on your career, it is likely that you will be involved in information technology initiatives. During the course of a project, you may have to critique user interface choices.

The two main techniques for evaluating a user interface are 1) Empirical Evaluation (testing with users) and 2) Heuristic Evaluation (based on a set of rules).  While empirical evaluation is by far the best technique, mastering Heuristic Evaluation is also a necessary skill.

 

Heuristics are rules developed over time by trial and error that have shown to work.  For example, when you play chess, you are better off using established initial moves.  Those initial chess openings are heuristics that have been proven to work over time.

In user interface (UI) design, one of most frequently referred lists of heuristic is the Jacob Nielsen’s ten Heuristics.

10 Key User Interface Heuristics

 

  • Visibility of System Status (The system should always keep users informed about what is going on.  For example, the progress during a file transfer.  Provide immediate feedback, etc.)
  • Match between system and the real world (The system should speak the user’s language, with words, phrases, metaphors and representations familiar to the user.)
  • User control and freedom (Supports undo and redo actions.  Allow user to override the system.)
  • Consistency and standards (Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow behavior user except and platform conventions.)
  • Error prevention (Prevents a problem from occurring in the first place.  Be permissive to various entry formats.)
  • Recognition rather than recall (Making objects, actions, and options visible. Make navigation visible and make it easy to go back, go to home page and quit.)
  • Flexibility and efficiency of use (Speed up the interaction for the expert users with accelerator.  Experts prefer few screens with a lot of information and a lot of flexibility in the methods, while novice users prefer going through step by step sequences with little information.)
  • Aesthetic and minimalist design (Dialogues should not contain information that is irrelevant or rarely needed.  In other words, present only necessary information for the task, rarely used information should be in secondary screens or windows.)
  • Manage errors (Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.
  • Help and documentation (Use prompt and contextual help related the task, allow easy search.)

Applying Heuristics

The impacts of heuristic depend of the context of use.

For example, a user interface might not be perfectly consistent as a whole (for example, location of a button might vary in different sections of the user interface), but the impact will be low if different users go in those different sections while the impact will be high if it is the same users.

Consequently, it would be wrong to rate user interface solely, and compliance to set of heuristic since the impact of each one of them depend of the context of use. For example, it is wrong to say that the CNN web complies at 75% while the New York Times web site complies at 88%.

  1. Prior to applying heuristics, it is essential to have a good grasp of the user profile and task.  User Profile comprises a description of the user frequency of use (once in a lifetime or everyday), familiarity with technology, gender age, and training, etc. The task description comprises: what are the user Goal, Sub goal and Methods and Frequency (looking for flight arrival 95% of the time, booking a flight 5% of the time)
  2. Get three to five independent evaluators that share the list of heuristics, user profile and task.  Each one of them evaluate the user interface during one or two hours separately
  3. Share the findings together and rate each problems in term of high medium and low impact.  High impact problems prevent user from performing their tasks while low impact might be an aesthetic aspect or a nice-to-have feature.

Training on User Interface Evaluation

 Cognitive Group offers training on User Interface Evaluation and heuristics. To know more on the user interface evaluation, see Usability Heuristics.

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