Testing with Humans
Testing with Humans by Giff Constable
What This Is 🤔
A practical guide to testing assumptions through real-world experiments, Testing with Humans focuses on how to move from conversation to evidence. The book shows how to design small, fast, and ethical experiments that reveal what people actually do—not just what they say.
It builds directly on customer discovery by translating insight into validation.
What It’s For 🎯
This book helps readers:
Test risky assumptions before committing significant resources
Design experiments that generate real learning
Reduce uncertainty in early-stage innovation
Avoid building solutions based on untested beliefs
Make evidence-based decisions under ambiguity
It is especially relevant for entrepreneurs, innovators, product teams, and anyone working with early-stage ideas.
What You’ll Find Inside 🧰
The book provides guidance on:
Identifying the riskiest assumptions in an idea
Designing simple experiments to test them
Choosing appropriate metrics and signals
Interpreting results without self-deception
Iterating based on evidence rather than opinion
The emphasis is on learning speed and decision quality, not perfect experiments.
How to Use It 🧭
This book works best as:
A hands-on manual during early product or service development
A companion to Lean Startup and experimentation-based methods
Background reading for innovation and entrepreneurship courses
A practical reference when deciding what to test next
It is meant to be used iteratively, alongside real projects.
Key Takeaways 💡
Experiments reduce risk more effectively than planning
Small tests can produce decisive learning
Behavior matters more than opinions
Evidence beats intuition under uncertainty
Testing early saves time, money, and momentum
Pro Tips 🧠
Test assumptions before refining solutions
Keep experiments small, fast, and reversible
Decide in advance what success and failure mean
Combine experiments with conversations for deeper insight