4 Experts

  • This image shows which evaluators found which usability problems in HE of a banking system.

  • Each row is an evaluator (n=19) and each column is a flaw (n=16).

  • Black squares show where evaluator found the problem.

  • The rows are sorted with most successful evaluators at the bottom.

  • The columns are sorted with easiest to find problems at right.

Here are some questions you can ask yourself about the graph:

  1. How can you define “Easy” and “Hard” to find problems?

  2. State some reasons a problem may be easy or hard

  3. Is there any problem that every evaluator found?

  4. What are the main lessons?

Heuristic evaluation is referred to as discount evaluation when 5 evaluators are used. For this graph, how well will 5 evaluators do?


This curve shows how many times the benefits are greater than the costs for heuristic evaluation of a sample project using the assumptions discussed in the text. The optimal number of evaluators in this example is four, with benefits that are 62 times greater than the costs.

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