How BTest Works: Key Concepts and Best Practices

Quick BTest Checklist: Setup to Success

1. Define your goal

• Clarity: Specify a single measurable objective (e.g., increase signup rate by 10%).
• Metric: Choose the primary metric to track (conversion rate, CTR, time on page).

2. Identify variants

• Control: Note current version.
• Variants: List 1–3 specific changes (headline, CTA color, layout).
• Hypothesis: For each variant, write a one-line hypothesis (If we change X, then Y will improve because…).

3. Determine sample size & duration

• Sample size: Estimate required sample using an A/B test sample size calculator (assume baseline conversion and minimum detectable effect).
• Duration: Run long enough to reach required sample and cover weekly variability (minimum 1–2 weeks).

4. Set up tracking

• Analytics: Ensure analytics tool captures primary metric.
• Event tracking: Implement and verify events (use test events).
• Segmentation: Define segments to analyze (mobile vs. desktop, new vs. returning).

5. Randomization & targeting

• Randomization: Confirm traffic is evenly randomized.
• Targeting: Apply any audience filters (geography, traffic source) consistently across variants.

6. Quality checks before launch

• Visual QA: Verify variants render correctly on major devices/browsers.
• Functional QA: Test conversion funnels end-to-end.
• Bot filtering: Enable bot/exclusion filters to avoid skewed data.

7. Run the test

• Monitoring: Check daily for technical issues, not early significance.
• Avoid peeking: Don’t stop early based on short-term spikes.

8. Analyze results

• Statistical significance: Use pre-defined thresholds (e.g., 95% CI) and check for sufficient power.
• Practical significance: Consider effect size and business impact.
• Segment analysis: Validate results across key segments to detect heterogenous effects.

9. Decide & act

• Winner: Choose variant based on statistical and practical significance.
• Implement: Roll out winning changes permanently.
• Document: Record setup, hypothesis, results, and learnings.

10. Iterate

• Next test: Use insights to form the next hypothesis.
• Long-term tracking: Monitor KPI post-implementation to ensure lift persists.