Medical Device Design for UsabilityMedical devices that are designed for good usability will minimize user errors. Negative outcomes are more likely to occur as a result of user error than of other device failure modes.

In their paper, Evaluating and Predicting Patient Safety for Medical Devices with Integral Information Technology JaiJie Zhang and colleagues discuss using heuristic analysis as a technique for evaluating medical device designs for usability. Their principles can serve as a tool for evaluating the usability effectiveness of a medical device design before product launch.

Heuristics in this context refer to the mental decision-making shortcuts we develop as a result of interacting with our environment. It is education we gain through experience. The authors identify 14 heuristics that can be used to evaluate medical device usability. Designers can increase the usability of their products by employing these rules:

  1. Be consistent. Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow standards and conventions of product design.
  2. Always keep the state of the system visible. Users should always be able to tell what is going on with the system through appropriate feedback and display of information.
  3. The image of the system perceived by users should match the mental model the users have.
  4. Keep the design as minimal as possible. Any extraneous information is a distraction and increases cognitive load.
  5. Minimize memory. Users should not be required to memorize a lot of information to carry out tasks. Memory load reduces users’ capacity to carry out the main tasks.
  6. Provide immediate feedback. Users should be given prompt feedback about their actions in a way that assures them the step was performed correctly.
  7. Design the system to be flexible in supporting different learning and use styles. Users always learn and users are always different. Give users the flexibility of creating customization and shortcuts to accelerate their performance.
  8. Provide meaningful error messages. The messages should be informative enough such that users can understand the nature of errors, learn from errors, and recover from errors.
  9. Prevent errors. Design interfaces to prevent errors from happening in the first place.
  10. Make sure there is clear closure. Every task has a beginning and an end. Users should be clearly notified about the completion of a task
  11. Actions should be Reversible to the extent possible. Users should be allowed to recover from errors. Reversible actions also encourage exploratory learning.
  12. Employ users’ language. Instructions should always be presented in a form understandable by the intended users.
  13. Provide users with a sense of control. Don’t give users the impression that they are controlled by the systems.
  14. Allow the system to provide help to the user when needed.