## 3 Methods
### System User Study
#### 3.5.5 Study Procedures  
Prior to commencement of the study, participants underwent a pretest questionnaire with informed consent to evaluate their familiarity with web-based and VR story co-creation experiences. Subsequently, participants were briefed on the experimental task and background. All participants, including those in the control and experimental groups, underwent a 10 min training session to acquaint themselves with the VR experimental procedures. Throughout the experiment, participants were encouraged to verbalize and document their thoughts. The formal study will involve 6 control groups and 6 experimental groups, evenly distributed due to the VR devices and platforms accommodating a maximum of four users per session. Six groups engaged with the web-based application _Story fork_, while another six groups interacted with the Co-Relay system, each session lasting 35 min. Following the completion of tasks, participants were required to complete a post-study questionnaire assessing user engagement, immersion, creativity, emotion, and socialization (refer to Tables 2 and 3). Subsequently, individual interviews were conducted with participants from both groups to elicit their reflections and feedback on the experience. Figure 8: Co-Relay VR Experience Interface and Interaction. (**A**) Participants engaging in the VR environment; (**B**) Interface showcasing participant task progress and messaging. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Classification of Indicators** & **Specific Indicators** & **Measurement Method** \\ \hline User Engagement & User Active Hours (Single/Cumulative) & System log statistics in the backend, comparing the difference in hours of use between VR and Web \\ User Engagement & Frequency of interaction (rediting/commenting/ collaborative operation) & Record the frequency of user operation per time (e.g., text editing, scene dragging and dropping, real-time comment response rate). \\ User Engagement & Content output (number of words/scenes/characters) & Quantify the output of story elements per time for a single person/team and compare the output efficiency of different platforms. \\ \hline Creativity & Diversity of story elements (characters/plot branches/media) & NLP tools to analyze text uniqueness, count the number of plot branches \\ \cline{2-3}  & & Design collaborative challenge tasks and record the number of innovative solutions produced by the team within the time limit. \\ \hline Emotional and social & Number of nodes in the collaborative network and number of messages & delivered Mapping user interactions, counting the number of core participant connections and the speed of team consensus building \\ \cline{2-3}  & Frequency of Sentiment Tagging and Positive Vocabulary Percentage & Counting the number of annotations through ‘emotion tags’, by analyzing the emotion vocabulary in the story content. \\ \hline Engagement: flow state & Score on a scale of 1–7, e.g., ‘the system keeps me focused’, combined with user interview recordings of ‘motivation to keep creating’ \\ \cline{2-3}  & Immersion: virtual environment presence Score & Score on a scale of 1–7, e.g., ‘being in the story scene’), combined with user interview transcripts ‘auditory/visual’ \\ \cline{2-3} Standardized questionnaire tool (Likert scale rating) & Creativity: Plot Originality and Cross-Media Integration Score & Score on a scale of 1–7, e.g., ‘’t think the combination of the VR scene and the text inspired my idea’ Combine this with the transcripts of the user interviews. \\ \cline{2-3}  & Emotional: Emotional & Score on a scale of 1–7, e.g., “‘new connections made” “’sense of being recognized””’ Combined with transcripts of user interviews \\ \cline{2-3}  & Social: Team Creation Experience & Rated on a scale of 1–7, ‘combined with user interview transcripts \\ \hline Objective statistical indicators & Demographic attributes & Percentage of age/gender/education (registration information or questionnaire collection) \\ \hline \hline \end{tabular}
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