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.

Why the lift is smaller than the raw difference¶

The lift Squoosh shows is an estimated real-world lift, not the raw difference between the synthetic shoppers.

Synthetic shoppers represent the part of your traffic a page change can actually move — the shoppers who are on the fence. Real traffic also includes people who would convert no matter which version they see, and people who would never convert. Because a page change can't sway those groups, Squoosh discounts the raw synthetic result to estimate the impact you'd expect on live traffic. The number you see is deliberately conservative.

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.