Usability

How usable an app or site is determines how effective it will be at performing the jobs for which it is hired. A site may have great content and the requisite features but if it’s unusable the value will not be realized. Usability is a conduit for value.

Guiding usability principles

Focus user attention on completing key tasks

Everything else that gets added to the user experience detracts from the user’s ability to do what they really need to do. Think before adding items like copy and links that promote anything other than serving user needs.

Use language familiar to entire target audience

Large organizations often suffer from Conway’s Law: ‘Organizations which design systems…are constrained to produce designs which are copies of the communication structures of these organizations.’ In other words, websites and applications designed by the City often imitate organizational structure, even when it doesn’t make sense to external users. To avoid this, always use language that is familiar and describes tasks.

Don’t require users to guess or explicitly remember anything

Use design elements and practices like:

  • Signifiers. Signifiers are visual elements, text, or other clues that help users understand what something is intended to do. For example, styling a link as a button helps signify that it can be clicked.
  • Accelerators. Accelerators are design patterns that speed up the performance of a task, even slightly. For example, double-tapping a photo in Instagram is an accelerated way to like the photo.
  • Feedforward. Whereas feedback is provided to users after an action happens, feedforward is copy or visual elements that provide guidance and nudge users in the right direction.
Help users avoid and recover from mistakes

Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action. Error messages should be expressed in plain language, precisely indicate the problem, and constructively suggest a solution.

Obvious always wins

It’s tempting to rely on icons without labels (or icons instead of labels) or to hide access to critical components of a site or application in a menu. This should be avoided because interface elements that are out of sight are also out of mind. When critical parts of an application are made more visible, usage of them can increase.