Table 7.

Summary of key findings on video quality and engagement across platforms.

Key finding	Data support	Interpretation
No significant difference in video quality between professional and non-professional uploaders	Table 5: All p > 0.05 for PEMAT, VIQI, GQS, mDISCERN	Professional credentials do not guarantee higher-quality public health communication.
No major inter-platform differences in information reliability (mDISCERN)	Table 4: mDISCERN-sum scores similar across platforms (p > 0.05)	All platforms face similar challenges in conveying reliable medical information.
Weak-to-moderate correlation between engagement and quality metrics	Table 6: Most r-values between 0.2–0.4; highest correlation: Bilibili Views vs. VIQI (r = 0.701, p < 0.001)	Audience engagement is poorly predictive of video quality; high views ≠ high quality.
YouTube leads in comprehensibility and actionability (PEMAT)	Table 4: PEMAT-T and PEMAT-A significantly higher on YouTube (p < 0.001)	YouTube videos are more structured and easier to understand and act upon.
Bilibili and TikTok lead in production quality (VIQI, GQS)	Table 4: VIQI and GQS significantly higher on Bilibili and TikTok (p < 0.001)	Short-form platforms excel in visual and production quality, but may lack depth.
TikTok has highest engagement despite shortest videos	Table 1: Median length = 114 s; highest likes, comments, shares	Algorithmic promotion and format favor high interaction, not necessarily quality.