Reading lift and confidence¶
The verdict band shows two numbers: lift and confidence. Lift is how much the variant changed your conversion rate. Confidence is how sure Squoosh is that the change is real. This page explains how to read both.
Lift¶
Lift is the difference between the variant and the original on your goal, as a relative percent. A lift of +22% means the variant converted 22% more often than the original. A negative lift means it converted less.
Under the lift, Squoosh shows a 95% CI — a range like +6% → +37%. This is the range the true lift most likely falls within. A narrow range means a precise result; a wide range means you have less certainty about the exact size of the effect, even if the direction is clear.
What the lift measures¶
The lift is the relative difference in conversion between your two shopper groups — how much more (or less) often the variant's shoppers converted than the original's. It is the shoppers' measured result, shown on the same scale as the per-arm rates in the evidence table, so the headline reconciles with the numbers below it. Squoosh does not discount or scale the number down.
The 95% CI under the lift is derived from the paired shopper decisions themselves — it bounds that measured lift and is never re-centered onto the headline. A wider range on a small sample is honest uncertainty about the exact size, not a hidden adjustment to the number.
Note
Sometimes the lift shows a 95% CI of —. This happens when the headline reflects the reviewer's judgment of the change rather than the raw shopper rate, where a numeric range wouldn't describe the figure. The lift is still meaningful; it isn't a measured rate with an interval.
Confidence¶
Confidence is how sure Squoosh is that the result is real and not random noise. Higher is more certain.
Squoosh calls a winner at 80% confidence. The meter shows your result against the 80% mark, so you can see how decisively the winner cleared the bar. Confidence is capped at 98% — Squoosh never claims to be completely certain.
There is one confidence figure per experiment: how sure Squoosh is about the winner versus the original. You won't see a separate confidence for each version, because the question a verdict answers is whether one beat the other.
For more on why the bar is 80% and how to reach higher certainty, see How Squoosh decides a winner.
Lift by segment¶
The evidence section breaks the lift down by audience segment, with a bar for each segment's change versus the original. A change can help one segment and hurt another — for example, +12% for returning shoppers and −8% for first-time visitors. The per-segment numbers blend back to the single headline lift, so use them to understand who a change worked for, not as separate verdicts.
The evidence section — arm conversion rates and confidence on the left, lift broken down by segment on the right.