Objective: Usability evaluation is now widely recognized as critical to the success of interactive health care applications. However, the broad range of usability inspection and testing methods available may make it difficult to decide on a usability assessment plan. To guide novices in the human-computer interaction field, we provide an overview of the methodological and empirical research available on the three usability inspection and testing methods most often used.
Methods: We describe two 'expert-based' and one 'user-based' usability method: (1) the heuristic evaluation, (2) the cognitive walkthrough, and (3) the think aloud.
Results: All three usability evaluation methods are applied in laboratory settings. Heuristic evaluation is a relatively efficient usability evaluation method with a high benefit-cost ratio, but requires high skills and usability experience of the evaluators to produce reliable results. The cognitive walkthrough is a more structured approach than the heuristic evaluation with a stronger focus on the learnability of a computer application. Major drawbacks of the cognitive walkthrough are the required level of detail of task and user background descriptions for an adequate application of the latest version of the technique. The think aloud is a very direct method to gain deep insight in the problems end users encounter in interaction with a system but data analyses is extensive and requires a high level of expertise both in the cognitive ergonomics and in computer system application domain.
Discussion and conclusions: Each of the three usability evaluation methods has shown its usefulness, has its own advantages and disadvantages; no single method has revealed any significant results indicating that it is singularly effective in all circumstances. A combination of different techniques that compliment one another should preferably be used as their collective application will be more powerful than applied in isolation. Innovative mobile and automated solutions to support end-user testing have emerged making combined approaches of laboratory, field and remote usability evaluations of new health care applications more feasible.