# Development and Validation of a Tool for VBOI (Virtual Body Ownership Illusion) Level Assessment
## 5 Conclusions  
This study presented a VR-BOI evaluation tool applicable in VR environments with various conditions involving the presence of virtual bodies. This evaluation tool consists of the following sub-attributes related to Virtual BOI: Embodiment, Presence, Visuo-tactile, Visuo-proprioceptive, and Visuo-Motor. Based on sub-attributes that can be perceived in one's body, and conditions allowing the evaluation of Virtual BOI based on these changes, we constructed the evaluation tool. We derived conditions that could induce different levels of Virtual BOI through a literature review. This includes perspectives (1 PP/3 PP), haptic feedback (Haptic/Non-Haptic), and interaction methods (Controller/Hand Tracking). The evaluation tool allowed us to assess the induced Virtual BOI levels under each condition, and we conducted statistical validation processes, including Confirmatory Factor Analysis (CFA) and Analysis of Variance (ANOVA), to verify the reliability of the evaluation tool. We aimed to validate the consistency of the evaluation tool's sub-scales through Confirmatory Factor Analysis (CFA). Through this, we removed three items with factor loadings < 0.5 and derived [PERSON]'s alpha scores for each sub-scale based on the remaining items. All five sub-scales, Embodiment, Presence, Visuo-proprioceptive, Visuo-tactile, and Visuo-motor, demonstrated [PERSON]'s alpha scores > 0.6, indicating the high reliability of the evaluation tool proposed in this study. In this study, to validate the accuracy of the evaluation tool, hypotheses derived from previous research were formulated, and the Virtual BOI scores obtained from experiments were examined to determine whether they aligned with these hypotheses. The results confirmed that all hypotheses were supported. First, we examined whether Virtual BOI scores varied across the four conditions presented in the experiment. ANOVA results revealed statistically significant differences in Virtual BOI scores among the conditions. Furthermore, among the conditions, Condition 1 with a first-person perspective using a controller with haptic feedback and Condition 2 with a first-person perspective using hand tracking both showed Virtual BOI scores of 5 or higher. On the other hand, Condition 3 with a third-person perspective exhibited the lowest Virtual BOI scores, in the range of 3 points. [PERSON]'s test results indicated significant differences between the first-person  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Dependent Variable** & **Conditions** & **Mean** & **SD** & **F** & \(\mathbf{p}\) \\ \hline \multirow{4}{*}{ \begin{tabular}{c} Visuo- \\ proprioceptive Score \\ \end{tabular}  } & Condition 1 & \multirow{4}{*}{5.5} & \multirow{4}{*}{0.79} & \multirow{4}{*}{45.07} & \multirow{4}{*}{\(<\)0.001} \\  & (1 PP)  
perspective conditions and the third-person perspective condition, demonstrating that perspective plays a significant role in inducing Virtual BOI. We also aimed to investigate whether the scores of sub-scales varied according to the conditions. Therefore, we compared the Embodiment scores and Visuo-tactile scores of Condition 1 and Condition 4, which differed only in the presence of haptic feedback, as well as the Embodiment scores and Visuo-proprioceptive scores of Condition 1 and Condition 3, which differed only in the perspective condition. ANOVA results showed that the scores of the sub-scales also differed among the conditions. Specifically, Condition 1 exhibited higher scores than Condition 3 and Condition 4, with statistically significant differences. These results indicate that the sub-scales proposed in this study sufficiently reflect the physical environmental conditions provided in the VR environment. The evaluation tool proposed in this study can be utilized as an assessment tool for various fields of VR environments, including games and clinical therapy programs, related to Virtual BOI. Virtual BOI serves as a measure, especially in clinical therapy programs, to indicate how immersed patients are in VR therapy.