> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://support.thumbnailtest.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# What is A/B Testing?

Normally, an A/B test is when you show 100 people something, 50 see A and 50 see B, then you judge if A or B is better based on their reactions. So, a thumbnail A/B test means we show thumbnail A for one day/ hour, then thumbnail B for one day /hour, and repeat that for a couple weeks. At the end, we see which thumbnail more people clicked on.