For each organisation, fifteen to twenty users were recruited to participate in a user experience
evaluation experiment. A combination of convenience and snowball sampling was used. The
Tobii Studio software used to record their eye tracking data indicates the accuracy of the
captured data and the data of participants with accuracy lower than 60% were not included in the
data set. Table 1 describes the participant groups whose data were included. Two studies
included 15 users and one 14. A samples size of 16±4 is accepted as adequate for usability
studies (AlRoobaea & Mayhew 2014).