The comparison chart

The comparison chart visualises the posterior distributions for each variant. Each distribution shows the range of plausible values for the true conversion rate (or other primary metric) of that variant.

Reading the shapes

Narrow distributions indicate high certainty about the true value. Wide distributions indicate uncertainty, typically because there is not yet enough data. When distributions overlap heavily, the variants are performing similarly. When they are clearly separated, there is strong evidence of a real difference.

Using the chart

The chart helps you understand not just which variant is winning, but by how much and with what certainty. A narrow distribution centred on 3.1% conversion rate tells you more than a point estimate alone.