Designers are often tempted to use icons to create a specific visual theme or mood for a software interface or website.
Usability specialists usually advise clients to be careful when using icons, and to only use them when the add to the user experience, or are very clear and not open to misinterpretation, like a standard print, back or home icons.
If your site relies on icons for navigation, and your visitors and customers don’t “get” what the icon “does”, they are in for a rough ride.
Counter-intuitive icons make things frustrating for the user because they make a lot of incorrect assumptions and selections as they try to get something done. Systems that make people “feel stupid” do not succeed.
If you think your customers would benefit from the use of icons in your interface, perhaps for an online game that needs a lot of player controls, then it makes sense to test the icons to make sure they can be quickly and correctly interpreted.
2 Types of User Testing Methods for Icons
Here are two ways to conduct icon usability tests:
- Icon intuitiveness test in which an icon is shown to a small number of users (typically 5) without its worded label. The users are asked to state their best guess as to what the icon is supposed to represent. This test assesses the degree to which the graphic chosen for the icon represented the intended concept.
For commonly used icons like Home and Print this is quite straight forward. An icon for an accounting application that ran a “Trial Balance” would be much more difficult to design and be correctly interpreted.
If you need lots of icons for your application, this is a great way for getting some quick feedback on intuitiveness which can then be added to your prototyped interface for user testing.
- Standard usability test in which the icons were shown to users as part of the full user interface and where the users are asked to “think aloud” as they use the system to perform set tasks. This test accesses the degree to which the icon would work well in context of the interface as a whole (where it would typically be displayed with a label).
When icons are viewed in context, test participants are in a better position to make educated guesses as to the purpose of the icon.
By asking the user to think aloud, you can hear the label they mentally assign to the icon, and see if they make a correct interpretation of its purpose.
4 Techniques for Measuring Icon Intuitiveness
There are 4 further techniques you can use to assess how intuitive a set of icons are as you run the test. You’ll need to observe the user and record the time taken to do 4 key mental processes, which gives some great quantitative and qualitative feedback on your icon set.
- Speed of selection
Speed measures how quickly an icon is selected by a user compared with the average. The quicker the correct icon is selected, the more intuitive (or learnable) it is.
As an example, I’ve picked out some home icons here. Most of them are pretty standard, except the igloo on the bottom left. Without the other “house-based” home icons to guide the user, using an igloo icon would be confusing for a significant number of test participants.
Association measures the percentage of users within the sample that assigned an icon with a particular term. The higher the association figure, the more intuitive the icon design.
- Multiple association
Multiple association measures how often an icon was assigned to other terms by participants. Icons that get multiple terms assigned to them are less intuitive than one that consistently gets a single term applied to it more often.
- Ask participants for verbal descriptions
Also ask the users to comment on what comes to mind when they see an icon. In Nielsen’s study, users commented on an icon that had been drawn for a link to some resources for software developers. The first iteration clear had problems with the users stating the following (surprising) things came to mind:
- thunder and lightning
- electric – looks painful
- person being killed by technology
- dance machine
- why do Sun developers look bug-eyed?
- Make sure your icons have a clear meaning, and avoid any unintended sub-conscious meanings too!
Icons can suffer from poor usability and I always recommend using words rather than pictures to convey meaning, as they are more intuitive and can also help with search engine optimization if your navigation contains useful keywords.
Sometimes, though, the nature of a project means icons are the only choice, especially for smaller display areas like mobile phone screens, where there often isn’t room for a lot of words.
So remember, when you need to incorporate icons into your interface, make sure you conduct some user testing and refine the icon designs to make them as intuitive and memorable as possible.