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The results page shows a small time to decision hint under the verdict:
Roughly 4 more days at current traffic to reach a call.
Two useful things it does:
  • Answers “how long do I need to wait” without having to think.
  • Sets expectations before someone else asks.

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What the estimate does

Simple projection:
  1. Look at the current confidence-interval width for the primary goal.
  2. Estimate the sample size needed to shrink the CI to the width that would clear the confidence gate.
  3. Divide by the current visitors-per-day rate.
That is it. No forecasting model.

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What it is not

  • A guarantee. Traffic can change, effect size can regress to the mean.
  • A green light to stop early. The verdict copy is what says the test is done. A “3 days to decision” hint means “keep going”, not “you can call it in 3 days regardless of the verdict”.
  • Always available. Very early tests or tests where the effect is tiny show “cannot estimate yet”.

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When it says “cannot estimate yet”

  • Not enough data yet. Wait a day.
  • The effect is so small the CI is not shrinking. A near-zero true effect can leave the CI wide forever.
  • Traffic is very uneven. If most of your visitors came on one day and traffic dropped since, dividing by average visitors-per-day misleads. The estimator is careful and refuses a bad guess.

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How to use it

  • Under a week? Almost always keep going.
  • A month or more? Consider whether the test is worth waiting for. Sometimes the honest answer is “the effect is too small to be worth detecting”, and the business call is to move on.
  • “Cannot estimate yet”? Keep going. Come back in a day.

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If you are impatient

The sequential engine (see the engines page) is designed for peeking. Switch to it on the next test, you can look as often as you like without inflating your false-positive rate.