Tuesday August 19th, 2014 by Björn Balazs and Heiko Tietze
The introduction of the new Breeze icon set in KDE let us again wonder, what aspects of an icon set actually takes what impact on the usability of it. We investigated Oxygen and Tango icons for the LibreOffice project before, but our focus then was on checking all icons of the standard tool bar. This time we focus on different icon sets and will use 13 common actions to compare them.
With this series we are going to test at least 10 different free icon sets: Breeze, Oxygen, Tango, Faenza, Nuvola, Nitrux, Elementary, Crystal Project, Humanity and Treepata. These icon sets differ on various aspects: use of color and details, flat or not and sometimes even on the metaphor used.
So, we generally want to analyze effects of icon design on the overall performance of an icon set. Statistics on this issue can obviously only be done after all icon sets have been tested. But with every test, we win some specific insights in strengths and weaknesses of each icon set tested.
In this post we share some findings about the Oxygen icon set.
The study was finished by 728 participants (drop-out rate 16%) with an average handling time of 2:57 min.
Results of Oxygen icons
Table 1 lists the aggregated quality indicators. They show how well all icons that we used for the test were suited to symbolize the different terms. It has a range from 1 (no fit) to 10 (perfect fit), whereas you would expect values of at least 9 for well represented terms.
Table 1: Quality of the icon set for different terms based on assignment ratio (percentage of missing assignments) and conspicuity (or speed of picking icons).
Table 2 shows a cross-table with the percentage of false associations. These are terms where the intended icon was not chosen by the users, but some other icon was.
Table 2: Cross-table of icons and terms with percentage of false associations. The direct match is inverted (1-value, e.g. 0.92 for Add) to obtain comparable data.
The Oxygen icon set performs very well in general. Most icons are quickly and reliable identified with the corresponding term. As found in previous studies there is a minor setback for Add/New, Undo/Redo, and especially Copy/Paste which are mutually mistaken. Also the Search icon shows quite a high number of missing values. Perhaps the field glasses are not such a good metaphor.
If you know how to design icons and would like to help us to identify metaphors that work better, please contact us. Also, all raw results are publicly available on our open usability platform UserWeave.
These results only reflect the internal quality of the Oxygen icon set. The final interpretation will be done after all sets have been tested. So stay tuned and please participate in our follow-up tests. And, of course, feel free to discuss these findings with us.