Best Practices for Experimentation Culture: 15 Rules That Work

These are the experimentation best practices that separate high-performing teams from the rest. Based on observations from hundreds of product teams.

Hypothesis & Planning Best Practices

1. Write Hypotheses Before Building

Every experiment needs a hypothesis written before implementation begins. The format:

"We believe that [change] will result in [outcome] because [reasoning]."

Example: "We believe that adding social proof badges will increase checkout conversion by 5% because users trust peer validation."

2. Define Success Metrics Upfront

Decide what you'll measure before launching. Include:

3. Calculate Sample Size in Advance

Determine how many users you need and how long the experiment will run. Don't stop early for positive results or extend for negative ones.

4. Document the Minimum Detectable Effect

What's the smallest change worth shipping? If you need 10% improvement to matter, design your experiment to detect that level.

Running Experiments Best Practices

5. Don't Peek at Results

Set a runtime and stick to it. Peeking inflates false positives. Use sequential testing methods if you must check early.

6. Run Experiments to Completion

Stopping experiments early based on results leads to wrong conclusions. Let them reach planned sample size.

7. Only Test One Variable

Multivariate tests are tempting but hard to interpret. Start with A/B tests of single changes.

8. Keep Control Groups Stable

Don't change the control during an experiment. Any modifications restart the clock.

Analysis Best Practices

9. Look Beyond the Primary Metric

Check secondary and guardrail metrics too. A conversion win that tanks revenue isn't a win.

10. Segment Results Thoughtfully

Look at how different user groups respond. But don't mine for segments that show significance.

11. Document Surprising Results

When experiments contradict intuition, write down why. These learnings are valuable for future hypotheses.

12. Make Decisions Within One Week

Set a deadline for acting on results. Experiments that sit in limbo waste the team's effort.

Culture Best Practices

13. Celebrate Learning, Not Just Wins

A well-run experiment that disproves a hypothesis is still valuable. It prevented shipping something that wouldn't work.

14. Share Results Broadly

Post experiment outcomes where everyone can see them. Use Slack, all-hands, or dashboards to make results visible.

15. Track Experiment Velocity

Measure experiments launched per month. High-performing teams run 10+ experiments monthly. Track this as a team metric.

Implementation Checklist

Use this checklist for every experiment:

Before launch:

During experiment:

After experiment:

Getting Started

You don't need to implement all 15 practices at once. Start with:

• Write hypotheses for every experiment
• Define success metrics before launching
• Share results in a public channel

These three practices alone will significantly improve your experimentation program.