The shortest version that still lands the one idea. Test two lengths.

Length is the best-evidenced lever for completion. Cut every short video to the shortest version that still delivers the one idea, and test two lengths. There's no source for "viewers decide in three seconds".
P Evidence: promising. Good studies, but small or few. Use it and keep checking.
Coimbra Vieira et al. 2026 · Zannettou et al. 2024.
Not medical, legal or financial advice.
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