How to Run Experiments That Don't Suck

A practical guide on when to run A/B tests and how to make them actually useful

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Dear subscribers,

Today, I want to talk about how you can run experiments that don’t suck.

Eric Metelka is head of product for Eppo where he has a broad view of how fast growing companies run experiments. I spoke to Eric about:

1. When to run experiments

2. How to run experiments that don’t suck

3. How to introduce experimentation to your company

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When to run experiments

Welcome Eric! How do you decide if you should run an experiment or not?

You should run experiments if you need to…

1. Prove causality. We’ve all attended meetings where people question if a product moved a metric. An experiment removes this uncertainty.

2. Measure impact. For example, you may run an experiment that grows engagement by 3% but hurts revenue by 1%. Measure impact to make decisions.

You should not run experiments if you need to…

1. Make a decision quickly. Experiments usually take time and work to run. They shouldn’t be used to make every product decision.

2. Bet on a 0-1 product. If you’re building something new, you might have too few users or not enough data to run an experiment.

3. Do a big launch. If you need to make a big public launch, it’s hard to experiment.

As a rule of thumb, experiments are most useful when you have product market fit and scale. They’re great for optimizing key user flows like onboarding, engagement, and checkout.

How do you run an experiment?