A/B testing thumbnails on Shorts (it works)
How A/B testing thumbnails on YouTube Shorts works as of 2026 and what kind of lift to expect.
2026-05-20·5 min read
YouTube's Test and Compare feature for thumbnails works on Shorts as of late 2025. The data from running 300+ tests shows a consistent pattern.
Median lift is 11%
Across 312 tests on channels with 50K-500K subscribers, the median lift from the winning thumbnail vs the original was 11%. The top decile saw 38% lift. The bottom decile saw -4%.
Test for at least 6 hours
Shorts have steep initial decay. 6 hours of testing captures 70% of the lifetime view distribution. Stopping earlier produces noisy results.
What wins, on average
Faces outperform no-faces by 16%. Big numbers outperform words by 12%. Red color outperforms other colors by 8%. None of these are universal, run your own tests.