## 5 Methodology
### Data Collection
#### 5.2.1 Questionnaire  
Nine types of questions were used with the following objectives:  
* To identify the participant's perceived stress condition;
* To identify the restorative outcome of the participants;
* To identify the perceived usability of the system that implemented the design elements proposed in the framework in reducing stress;
* To identify the perceived usefulness and ease of use of the system that implemented the design elements proposed in the framework in reducing stress;
* To identify the perceived effectiveness of the system that implemented the design elements proposed in the framework in reducing stress;
* To identify the usefulness of the design proposed in reducing stress. (i) To identify the participant's perceived stress condition  
Three questions were used to identify the perceived stress conditions of the participants before and after the therapy session. The questions used were (i) the Depression Anxiety Stress Scale (DASS), (ii) a stress intensity scale and (iii) an emotional intensity scale. _Depression Anxiety Stress Scale (DASS)._ The Depression Anxiety Stress Scale (DASS) is a well-established self-reporting tool to assess the participant's mental health before experiencing a therapy session. The DASS consists of 42 items, including three emotional states, namely (i) depression, (ii) anxiety and (iii) stress. The questions required the participants to rate their feelings and thoughts during the past week on a 4-point Likert scale (from 0 = 'did not apply to me' to 3 = 'applied to me very much, or most of the time'). As this study focused on psychological stress, only 14 questions measuring the symptoms of stress were used. _Stress intensity scale._ In addition to the DASS question, this question was also used to measure the stress level of the participants. The question requested the participants to rate their current stress intensity level based on a 10-point Likert scale (from 1 = 'not at all stress' to 10 ='maximally stressed'). The participants were asked to rate their stress intensity level twice, before and after the therapy session. _Emotional intensity scale._ A question on current emotional state was also included to measure the participants' psychological disturbance. Six emotional states: (i) angry, (ii) worried, (iii) sad, (iv) tense, (v) exhausted, and (vi) restless were listed to be selected by the participants. These six emotions have been validated by a clinical psychologist as common words used in everyday conversations to represent a person's psychological state of stress. The participants were asked to choose an emotion that best described their current feeling and to rate the intensity of the selected emotion based on a 10-point Likert scale (from 1 = 'low' to 10 = 'high'). The intensity of the chosen emotion was rated twice, before and after the therapy session. (ii) To identify the restorative outcome of the participants  
Restoration outcome scale (ROS) statements, proposed in [30], were utilised to measure the restorative state of the participants. The ROS consists of six statements to be rated by the participants using a 7-point Likert scale (from 1 = 'extremely disagree' to 7 = 'extremely agree'). The participants were requested to rate the ROS statements twice, before and after the therapy session. (iii) To identify the perceived usability of the system that implemented the design elements proposed in the framework in reducing stress  
The system usability scale (SUS) is one of the most widely used standardised questions for the assessment of perceived usability [31; 32]. The SUS consists of 10 items, for which the participants had to rate each one based on a five-point Likert scale (from 0 ='stronglydisagree' to 4 ='strongly agree'). The participants were asked to rate the SUS once after the therapy session. For this study, the positive version of the SUS proposed by [33] was used to reduce the likelihood of response and scoring errors, misinterpretation and miscoding, due to the mixed-tone statement used in the original version of the SUS. 4.