You've done the initial research. Surveys and landing page tests suggest you're onto something. But do people just like your idea, or do they desperately need it? To find out, you need to go beyond asking people what they would do and actually observe what they do. This means testing your core value hypothesis with something more substantial.

This is where high-fidelity Minimum Viable Products (MVPs) come in. Unlike a simple landing page, these MVPs simulate the core experience of your product. Their goal isn’t to test a specific feature, but to answer a single, critical question: have you found a “hair-on-fire” problem that customers will actively pay—with money, time, or data—to solve?

Building a fully functional product to test a hypothesis is slow and expensive. Instead, you can use clever shortcuts that provide the experience of a working product without the code. Two of the most effective methods are the Concierge MVP and the Wizard of Oz MVP.

The Concierge MVP is a high-touch, manual service. You personally guide the user through the process, delivering the promised value by hand. There is no technology, just you acting as the product. This approach is perfect for testing complex services where you're still unsure about the ideal workflow or customer needs. You get rich, qualitative feedback because you're right there with the customer.

The Wizard of Oz MVP is different. It looks like a fully automated, functional product from the user's perspective, but behind the scenes, humans are pulling all the levers. The user interacts with a polished interface, unaware that their requests are being fulfilled manually. This is ideal for testing products that depend on complex algorithms or automation, like a recommendation engine or a data analysis tool. It validates whether customers want the outcome, before you invest in building the technology to deliver it automatically.

Once your MVP is in the hands of early adopters, the Build-Measure-Learn loop begins. You've built the experiment (the MVP). Now you need to measure the results and learn from them. But what should you measure? Many startups get lost chasing vanity metrics, while ignoring the actionable data that truly indicates product-market fit.

For example, 'Total Signups' is a classic vanity metric. A big number looks great, but it tells you nothing about whether people are actually using your product or getting value from it. An actionable metric would be 'Percentage of new users who complete a key action within their first session.' This number tells you if your product's value is clear and accessible from the start.

One of the most powerful actionable metrics for measuring product-market fit is retention, best visualized through cohort analysiss. A cohort is a group of users who started using your product during the same time period (e.g., 'January Signups'). By tracking each cohort over time, you can see what percentage of them remain active. If your retention curves flatten out over time, it's a strong signal that you've built something valuable that a core group of users can't live without. If every cohort drops to zero, you have a problem.

So how do you quantify that 'can't live without' feeling? The Sean Ellis Test is a simple but powerful survey that gets right to the heart of the matter. You ask your users one question: "How would you feel if you could no longer use this product?"

• A) Very disappointed
• B) Somewhat disappointed
• C) Not disappointed

If more than 40% of respondents answer "Very disappointed," you likely have achieved product-market fit. This benchmark, developed by Sean Ellis after analysing hundreds of startups, is a strong leading indicator of sustainable growth.

Based on this data, you face a crucial decision: pivot or persevere. If your metrics show flat retention and a poor Sean Ellis score, it may be time to pivot—to make a significant change to your product, strategy, or target market based on what you've learned. However, if your data shows a strong, sticky core of users, even if it's small, the right move is often to persevere—to double down on what's working and optimise the experience for those who already love you.

Ready to test your knowledge on validating your big idea?

Finding product-market fit isn't a single event but a process of rigorous, honest testing. By using the right kind of MVP and focusing on actionable metrics, you can replace guesswork with data and find the path to a product that people truly need.