Usability Testing of Instant Messaging Apps Using Measured and Self-Reported Data

Instant messaging apps are among the most widely used smartphone apps, but little research has been done on their usability. We conducted an experiment in which thirty volunteers used four common instant messaging apps for 2 to 3 weeks, and we observed their interaction with these apps in controlled conditions. We observed that effectiveness ranged between 69% and 96% and varied significantly (F = 19.551, p < 0.05) among the apps. Efficiency ranged between 50% and 70% and varied significantly (F = 5.447, p < 0.05). There was no major change in effectiveness and efficiency during the intervention period denoting low learnability. The satisfaction of the subjects varied significantly (F = 40.026, p < 0.05) for the apps. The affinity of three of the apps was above 75% denoting that three-fourth of the subjects who used them before the intervention planned to continue using them in the future. There was no strong influence of self-reported performance- and satisfaction related parameters on affinity.