Exercise 9: Diagnose Your Testing Programme | A/B Testing for Product Managers

A/B Testing for Product Managers

The Four Deaths

What a Test Can and Cannot Tell You

Why "Let's Just Test It" Is Often Wrong

The Shape of a Good Test

What This Course Covers

The Three Questions

When to Just Ship It

Test, or Go and Talk to Someone?

Exercise 1: Triage Your Test Ideas

Why "We Think This Will Improve Conversion" Isn't One

The Four-Part Hypothesis

Saying in Advance What Would Make You Wrong

One Change or Several?

Exercise 2: Write a Real Hypothesis

The Four Numbers

The Calculation, Worked Through

Why Most Tests Are Too Small

The Weekly Cycle Rule

Exercise 4: Do the Arithmetic Before You Build

Before You Turn It On

What to Check on Day Two

The Six Things That Invalidate a Running Test

Exercise 5: Set Up Properly

What "Significant" Actually Means

Effect Size and the Range

The Flat Result

When the Result Contradicts What You Believed

Exercise 6: Read a Result Properly

Winning Isn't the Same as Worth Shipping

Exercise 7: Decide and Record

Slicing Until Something Wins

Novelty and Primacy

Contamination, Mismatch and Survivorship

Exercise 8: Audit Your Own Results

Five Situations Where Testing Won't Help

What to Do With Too Little Traffic

Knowing When to Stop

Exercise 9: Diagnose Your Testing Programme

Final Project: Design, Run and Report One Real Test

Before You Build: Deciding Whether to Test

Before You Build: Writing and Stress-Testing a Hypothesis

Before You Build: Choosing Your Metrics

Before You Build: Sample Size and Duration

Running It: Pre-Launch Review

Reading It: Reading a Result Honestly

Reading It: Auditing for the Six Lies

Afterwards: The Test Readout

Checking Yourself: Is Testing Right for Your Situation?

Glossary: Words Explained

Lesson 4

Exercise 9: Diagnose Your Testing Programme

List your last five tests, their durations, and their results. Include the flat ones and the abandoned ones.
Count how many produced a clear decision. If it's under half, that's the finding.
Run the diagnostic prompt with honest inputs, including the tests that didn't go well.
Work out the smallest effect you can realistically detect on your main surface. Write it down, it's the threshold below which you shouldn't propose tests.
Check the stop signals in 9.3. If any describes you, write down what you'll do instead of running another test.