Jakob Nielsen defines 10 “usability heuristics” -i.e. generic empirically based principles of system design that have endured over 4 decades of radical changes in information technology:

 

1. Visibility of system status

Ensure users know where they are in the system and what will happen next. This may be as simple as using navigation and breadcrumbs effectively.

 

2. Consistency between system and the real world

Ensure that the system language matches the language of users, and that actions such as pressing a downward facing arrow on the screen reduce some variable or, for example, lowers an infusion pump flow rate.

 

3. User control and freedom

Allow the user to explore the system without committing mistakes and let them cancel any action without serious consequences.

 

4. Consistency and standards

• Ensure the same words and actions mean the same thing on all screens
• Locate commonly used information and data items such as title, drug name, condition in the same location on all screens
• Use consistent formats and units for data (eg. for drug dose, weight) wherever they appear. The Right Decision Service provides a style guide with information on expressing units of measurement

 

5. Error prevention

Use careful system and interface design to avoid errors in data entry. This includes:

• Item selection (eg. browsing a long alphabetical list of drug names can lead users to select an obscure drug like penicillamine when penicillin was wanted because it comes earlier)
• Providing controlled lists of options rather than free text entry. The Question-and-Answer tool enables you to create such controlled lists

 

6. Recognition rather than recall

Humans are better at recognising items rather than recalling items from memory. Design the interface to maximise item recognition and minimise reliance on memory recall. For example, users should be able to search by keyword to find a particular decision support tool or piece of guidance rather than having to remember its URL or exact location in the navigation structure. Similarly, you can provide ranges of physiological and biochemistry measures that are within and outside the normal range, rather than requiring the user to remember the precise figures.

 

7. Flexibility and efficiency

For example, adopt a layered approach to guidance, promoting simple, action-focused summary recommendations for non-specialist users, with links to more detailed underpinning evidence for specialists.

 

8. Aesthetic, minimalist design

Cut the clutter and unnecessary words. These can distract users from carrying out their core tasks.

 

9. Recognise, diagnose and help users recover from errors

Provide simple warning and error messages to help users return rapidly to normal working.

 

10. Help and documentation

A well-designed user interface may not need any documentation. However, given the varying levels of digital literacy among users, it can still be helpful to offer a “How to use” guide for those who are unfamiliar with apps or decision support tools.

Further information is available on the Nielsen Norman usability website.