Splice is considering an experiment on the Sounds landing page signup flow to increase the rate of visitors who create an account and start a free trial. Before launching, the Growth team wants to choose a minimum detectable effect (MDE) that is realistic, statistically defensible, and worth the engineering cost.
You are planning a two-arm A/B test with equal traffic split between the current signup flow (control) and a redesigned flow (treatment). Use the baseline conversion rate and traffic estimates below to determine the smallest lift the team can reliably detect in a 21-day experiment, and whether a proposed target lift is feasible.
| Metric | Value |
|---|---|
| Baseline visitor-to-trial conversion rate | 8.4% |
| Average eligible unique visitors per day | 52,000 |
| Planned experiment duration | 21 days |
| Traffic split | 50% control / 50% treatment |
| Significance level | 0.05 |
| Desired power | 80% |
| Proposed business target lift | 0.8 percentage points |
| Minimum worthwhile lift from business perspective | 0.6 percentage points |
Assume the primary metric is binary conversion at the user level.