THE IMPACT OF AGE ON RETROSPECTIVE THINK-ALOUD USABILITY TESTING

Abstract

Usability is a popularconcept which is used widely in HCI and has become increasingly important over recent years. In website engineering, usability is an essential component for the success and survival of websites. The Retrospective Think-Aloud (RTA) usability test is one ofthe two most popular think-aloud tests used widely by practitioners in HCI. The purpose of this study is to examine the impact of age on the outcomes of the RTA usability test. Three usability measures were considered (accuracy: task completion, efficiency: time on task, and satisfaction). An experiment including 60 participants from three different age groups (18-28; 40-50; 64-76) was carried out during the period spanning August-October 2018 to examine the impact of age on the given metrics. The data obtained were analysed using both descriptive and inferential statistics. The results were interpreted and showed that there were statistically significant differences in the average time of tasks based on the age where the young adults spending far less time on completing tasks compared to the older adults.The results showed that participants who were age 18-28 and 40-50 have more efficiency than participants who were age 64-76 and participants who were age 40-50 have more efficiency than participants who were age 64-76. The results also showed that there were statistically significant differences in the number of successful tasks based on the age where accuracy decreased with the increasing of age. Participants who were age 18-28 and 40-50 have more accuracy than participants who were age 64-76. However, the results showed that age did not affect satisfaction and there were no statistically significant differences existed in this regards. In addition to this, a list of the common usability issues faced by participants on the Absher website was discovered where the most common problems were the missing search icon, inconsistency with pop-up windows, and inconvenient colours for text and pictures.The results of this study confirmed the importance of age regarding the outcome of the RTA usability test; as such, it is recommended that age be considered when carrying out usability tests using RTA. It is also recommended that further investigation be conducted in this regard considering other characteristics, such as sex and years of education.