## 3 Usability Evaluation Methods
### Suss Score  
The system usability scale (SUS) is a widely used, standardized questionnaire that assesses perceived usability. In 2009, researchers reported that 43% of post-study questionnaires used in industrial usability studies incorporated the SUS [44]. Survey respondents rate statements about the system's complexity and whether they believe training or support is needed to use it effectively. According to [PERSON] [45], this simple, 10-item post-test questionnaire quickly assesses a product's usability without requiring complicated analysis. Table 3 presents the questionnaire.  
\begin{table}
\begin{tabular}{c p{142.3 pt} p{142.3 pt} p{142.3 pt} p{142.3 pt} p{142.3 pt}} \hline \hline \# & **Questions** & **Strongly Disagree 1** & **2** & **3** & **4** & **Strongly Agree 5** \\ \hline \multirow{2}{*}{1} & I think that I would like to use this system frequently. & \multirow{2}{*}{2} & \multirow{2}{*}{3} & \multirow{2}{*}{4} & \multirow{2}{*}{**Strongly Agree 5**} \\ \cline{1-1} \cline{5-5}  & I think that I would like to use this system frequently. & & & & \\ \hline \multirow{2}{*}{2} & I found the system unnecessarily complex. & \multirow{2}{*}{3} & \multirow{2}{*}{I thought the system was easy to use.} & \multirow{2}{*}{4} & \multirow{2}{*}{**Strongly Agree 5**} \\ \cline{1-1} \cline{5-5}  & I think that I would need the support of a technical person to be able to use this system. & & & \\ \hline \multirow{2}{*}{5} & I found the various functions in this system were well integrated. & \multirow{2}{*}{6} & \multirow{2}{*}{I thought there was too much inconsistency in this system.} & \multirow{2}{*}{6} & \multirow{2}{*}{I thought there was too much inconsistency in this system.} & \multirow{2}{*}{6} & \multirow{2}{*}{I thought there was too much inconsistency in this system.} & \multirow{2}{*}{6} & \multirow{2}{*}{6} \\ \cline{1-1} \cline{5-5}  & I would imagine that most people would learn to use this system very quickly. & \multirow{2}{*}{7} & \multirow{2}{*}{I would imagine that most people would learn to use this system very quickly.} & \multirow{2}{*}{7} & \multirow{2}{*}{7} & \multirow{2}{*}{7} \\ \cline{1-1} \cline{5-5}  & I found the system very cumbersome to use. & \multirow{2}{*}{8} & \multirow{2}{*}{I found the system very cumbersome to use.} & \multirow{2}{*}{7} & \multirow{2}{*}{7} \\ \cline{1-1} \cline{5-5}  & I felt very confident using the system. & \multirow{2}{*}{8} & \multirow{2}{*}{7} & \multirow{2}{*}{7} & \multirow{2}{*}{7} \\ \cline{1-1} \cline{5-5}  & I needed to learn a lot of things before I could get going with this system. & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 3: The system usability survey questionnaire.  
In general, the SUS can quickly, easily. and comprehensively evaluate usability. The SUS comprises 10 closely related questions on a 5-point Likert scale, of which questions 1, 3, 5, 7, and 9 are positive, and 2, 4, 6, 8, and 10 are negative. A higher SUS score implies better product usability.  
Evaluating the usability criteria requires expertise in both the customization of usability principles and their specific domain for wearable smartwatches. So, evaluators need a thorough understanding of all the challenges and considerations that should be kept in mind to develop effective heuristics. In turn, this involves extensive research, analysis, and iteration to ensure the heuristics accurately reflect the requirements and expectations of smartwatch users. Moreover, participants involved in the heuristics should be representative of the target user population, i.e., those who are professionals or fitness enthusiasts, which is a challenging task. Thus, the data acquisition, its analysis, and interpretation is a complex problem that is resolved in this study through careful planning and comprehensive analysis of the evaluation methods.