Software Usability/Human Interface Design

Usability should be designed into solutions

Usability refers to the ease with which people can employ a particular tool or other human-made object in order to achieve a particular goal. It is important for BAs to understand the principles of software usability to help design usability into all of their project solutions. If your organization employs usability professionals, request their involvement on your project early. If possible, include them in requirements elicitation so that they can learn about the business needs and the business environment as you do. If your organization expects usability design as part of the role of the business analysis professional, learn about the principles and concepts. Jakob Nielsen’s Usability Engineering is a great resource (Nielsen, 1993).

The International Organization for Standardization has defined a set of standards that detail the usability or dialogue principles of human/system interaction (ISO 9241 Part 110). Existing software interfaces can be assessed against these principles to determine the relative usability of existing software. As you read the principles, think about a software application with which you are familiar (e.g., Amazon.com). How well does it follow the principles?

1. Suitability for the task: This principle recommends that software functionality should be designed for the particular task the user is trying to accomplish based on the work required and the user’s skill level. This includes facilitating logical workflows and the software’s ability to work with other applications.

2. Self-descriptiveness: The interface should be intuitive and make it clear what the user should do next. Adherence to this principle eliminates the need for help systems and online procedure manuals.

3. Controllability: The user should be able to control the pace and sequence of the interaction and must be able to easily exit from the system whenever desired.

4. Conformity with user expectations: The software should behave consistently and as a user would expect. Whenever the software reacts differently than the user expects, there may be a usability issue (e.g., a user who clicks on a cancel button expects to be released from the current transaction).

5. Error tolerance: The software should be forgiving and be prepared to handle any user error. Error messages must be very clear and written in the user’s language. They should explain what error was made and how the user can correct the problem. In the most usable systems, software is built to anticipate and prevent user errors.

6. Suitability for individualization: The software should be customizable (i.e., menus, screen look) for individual users. Novice users should be provided help and expert users should be able to be highly productive.

7. Suitability for learning: The software should be simple and support learning so users can become more efficient and productive. It should use clear business terminology and minimize the user’s memory load.