Message Resonance Test Planner
Compare alternative value propositions or headlines with a calculated sample size and estimated test duration based on your real reach.
Add text to at least two variants before building the test plan.
Your test plan
Before you launch
Variants in this test
How it works
-
Set your test parameters
Choose a channel, goal metric, current baseline rate, the minimum lift worth detecting, and your expected daily reach.
-
Add your message variants
List the alternative headlines or value propositions you want to compare, at least two.
-
We calculate the sample size
Using a standard two-proportion approximation (95% confidence, 80% power), n = 16 × p × (1−p) / delta², where delta is the absolute lift implied by your minimum detectable effect.
-
Get an estimated test duration
Total sample size is split across your variants and divided by your daily reach per variant to estimate how many days the test needs to run.
Need concepts to test first? Try the Positioning Statement Builder, or read Validate Your Software Idea With Existing Tools First.
Frequently Asked Questions
How accurate is the sample size estimate?
It uses a standard two-proportion approximation for 95% confidence and 80% power — the same math behind most A/B test calculators. It is a solid planning estimate, not a substitute for a full statistics package if the decision is high-stakes.
What is "minimum detectable effect"?
The smallest relative lift over your baseline rate you care about detecting. A smaller MDE requires a much larger sample size — halving your MDE roughly quadruples the sample needed.
What if I do not know my baseline rate yet?
Use your best estimate from a comparable page, campaign, or industry benchmark. The plan will still be directionally useful — just revisit the sample size once you have real baseline data.
Why does adding more variants increase the sample size needed?
Each variant needs its own full sample to compare fairly against the others, so total sample size scales with variant count even though the per-variant size stays the same.
Can I test more than headlines with this?
Yes — the same test-planning logic works for email subject lines, ad headlines, and social post copy. Choose the closest channel option to frame the plan correctly.
How We Compare
| Feature | MVPHub Message Resonance Test Planner | Optimizely | Google Optimize-style spreadsheets |
|---|---|---|---|
| Calculates sample size from baseline rate and MDE | Included | Included | Not included |
| Estimates test duration from your actual daily reach | Included | Limited | Not included |
| Built for early message/headline tests, not full experimentation platforms | Included | Not included | Included |
| Full experiment deployment, targeting, and analytics | Not included | Included | Not included |
Optimizely offers full experimentation infrastructure and spreadsheet templates can hold a plan, but MVPHub calculates sample size and duration directly from your baseline, MDE, and reach without setup.