Abstract
This paper presents the results of a study that aimed to compare the utility and validity of the traditional concurrent think-aloud and the co-discovery usability testing methods. The study was conducted in Saudi Arabia and involved three points of comparison: number and nature of usability problems discovered, test participants' experiences, and overall task performance. The results show significant differences between the two types of testing methods. The co-discovery method led to the detection of a greater number of minor usability problems relating to layout and functionality. The participants also found the co-discovery method to be easier and less tiring to perform and more natural for them than the concurrent think-aloud method. No difference was found between the methods in terms of participants' task performance. The study concludes that the co-discovery method seems to be appropriate for identifying numerous minor issues and ensuring that the usability testing experience is as natural as possible for participants. However, the classic method seems to be a more cost-effective method, as it is equally useful in revealing high-severity problems and requires only one participant per test session.