Every result is a comparison to a baseline. The baseline is one
variant, treated as the reference, lift, CI, and verdict are all
relative to it.
By default the Original variant (position 0) is the baseline. That is
usually right. Occasionally it is not.
When to change it
- You are running Original, A, B, and A is your current champion.
Comparing B against Original mixes two changes. Set A as the
baseline; the page now compares B to A directly.
- The Original is a placeholder. Sometimes the Original is
synthetic, a control built specifically for the test that no real
visitor sees. Set one of the treated variants as baseline.
How
On the results page, click the Baseline dropdown in the meta bar
at the top. Pick a variant. Everything on the page recomputes with
that variant as the reference.
The URL updates to include ?baseline=<variantKey>. Share the URL
and your colleague sees the same view.
Resetting
Next to the dropdown, a small Reset chip appears once you have
overridden the baseline. Click it to return to Original.
What changes
- Lift numbers. Every variant’s lift is now vs the new baseline.
- Verdict copy. “Variant B wins” becomes “Variant B wins vs
Variant A”.
- CIs. The confidence intervals are computed as differences from
the new baseline.
- Charts. The over-time confidence chart plots the new baseline
as zero.
What does not change
- The data. Every event is still counted the same way.
- The test itself. No visitors are re-bucketed; the baseline is a
display choice only.
With segments
Baseline override composes with segments, pick
a segment first, then change the baseline, or vice versa. Both end
up in the URL and share cleanly. Last modified on August 1, 2026
