You've identified your target market and built a product you believe solves their problem. But belief isn't enough. Before committing to a full-scale Go-To-Market (GTM) strategy, you need proof that your product isn't just a 'nice-to-have', but a 'must-have'. This is the core of validating product-market fit (PMF). The goal is to find out if your solution addresses a problem so significant that customers would be genuinely lost without it.

This means moving beyond theoretical interest to proven demand. We need to find the users who feel the pain most acutely. These aren't just any customers; they are your High-Expectation Customers (HXCs). An HXC is the most discerning person within your target demographic. If you can satisfy them, you can likely satisfy the entire market. They have already tried other solutions and found them lacking. They recognize the problem you're solving and have a clear idea of what a great solution looks like. Finding and listening to your HXCs is the first step toward rigorous validation.

The most direct way to measure PMF is by asking your users a simple question. The Sean Ellis test provides a clear, quantitative benchmark to determine if your product has crossed the threshold from interesting novelty to essential tool. It's built around a single, powerful survey question.

You offer three possible answers: 'Very disappointed', 'Somewhat disappointed', or 'Not disappointed'. The rule is simple: if at least 40% of your users select 'Very disappointed', you have likely achieved strong product-market fit. This segment represents your core group of advocates who truly depend on your solution.

When designing this survey, timing and targeting are key. You shouldn't send it to brand new users who are still exploring. Instead, target users who have experienced the core value of your product. A good rule of thumb is to survey users who have been active for at least two weeks or have completed a key workflow twice.

Follow up the main question with open-ended ones, such as:

• What is the main benefit you receive from this product?
• How could we improve this product for you?

This qualitative feedback is invaluable. The responses from your 'very disappointed' group will tell you why your product is a must-have, helping you to double down on what works.

Surveys are powerful, but user behaviour provides the ultimate proof. Retention data is your most honest PMF indicator. A retention curve that flattens out over time is a classic sign of product-market fit. It shows that after an initial drop-off of users for whom the product wasn't a good fit, a core group sticks around because they get consistent value.

Beyond just sticking around, how deeply are users engaging? High retention combined with deep usage is a powerful signal. Are they using advanced features? Is the frequency of use increasing? This indicates your product is becoming integrated into their regular workflow, solving what's known as a 'burning platform' problem—a high-value issue that they urgently need to solve.

Conversely, high churn—the rate at which customers stop using your product—is the clearest sign of poor PMF. If users leave shortly after signing up, your product failed to deliver on its promise or solve a meaningful problem for them.

By combining direct feedback from the Sean Ellis test with behavioural data from retention and usage, you can build a confident, evidence-based case for your product-market fit. Only then is it time to hit the accelerator on your GTM strategy.