4.2.4. Measures

Socio-demographic questionnaire—A self-constructed socio-demographic questionnaire was used to collect socio-demographic information (e.g., gender, age, ethnic background) and general information concerning participants' previous smartphone use.

Problem Areas in Diabetes Questionnaire [59]—The Dutch translation of the Problem areas in Diabetes (PAID) was used to examine diabetes related emotional distress. It consists of 20 items on a 5-point Likert scale. An example item is "Feeling scared when you think about living with diabetes". In the current study, the total PAID score was used as an indication of the patient's diabetes related emotional distress before and after using the PERGAMON platform. A score of 40 or higher is considered to be an indication of "emotional burnout". This questionnaire demonstrates good psychometric characteristics and the Dutch version used has been validated with patients in the Netherlands [59].

System Usability Scale (SUS; Dutch translation [60])—The Dutch translation of the SUS was used to measure usability of the PERGAMON platform. This questionnaire consists of 10 items on a 5-point Likert scale ranging from strongly agree to strongly disagree. An example item is "I thought the system was easy to use". A score above 68 is interpreted as above average usability and below 68 is interpreted as below average. This questionnaire is internationally acknowledged as a reliable questionnaire to measure system usability [60].

Semi-structured interview—A semi-structured interview was used during group discussions (focus groups) to explore user experiences of the PERGAMON platform with regard to design, enjoyment, storyline, ease of use, educational value, engagement and innovative aspects of the platform (e.g., the virtual coach, sensors, serious games), as well as their overall judgment about the PERGAMON platform.
