The Go-To-Market Health Check: Diagnose with the 4 Fits

Hi there,

When growth flatlines, it’s easy to focus on what’s visible—declining web traffic, lower engagement, rising acquisition costs. But these are often just symptoms of a deeper issue. 

The real challenge isn’t just spotting these problems—it’s understanding what’s causing them.

That’s where I often refer to Brian Balfour’s 4 Fits Framework. More than just a model; it’s a diagnostic tool to pinpoint what’s really holding your Go-To-Market (GTM) strategy back.

TL;DR: A Quick Guide to Diagnosing GTM Misalignment

If growth has stalled, the issue might not be what you think. Use the 4 Fits to diagnose where friction is holding you back:

1️⃣ Market–Product Fit: Are we solving a real, urgent problem for a defined market?
2️⃣ Product–Channel Fit: Does our product align with how customers naturally discover and buy?
3️⃣ Channel–Model Fit: Can we scale profitably through our chosen channels?
4️⃣ Model–Market Fit: Does our business model match how the market wants to pay?

Skip to the section that resonates most or read on for a full breakdown.

The 4 Fits: A Health Check for Sustainable Growth

Think of the 4 Fits like a health check for your Go-To-Market strategy. Each "FIT" helps you identify a specific kind of misalignment. If even one is off, growth stalls; no matter how hard you push elsewhere.

1. Market–Product Fit

📌 Are We Still Solving the Right Problem for Many?

Symptoms of Misalignment:

• Low customer demand

• Poor retention

• High churn

The Diagnostic Lens: 
“Do we have a product that solves a meaningful problem for a well-defined market?”

Misalignment here often comes from assumptions. Assuming we know the customer’s problem, what they value, or how urgent it is. That’s why the key to diagnosing Market–Product Fit isn’t guessing; it’s listening.

Voice of the Customer (VoC) isn’t just a nice-to-have; it’s how you diagnose the problem accurately.

• Customer Conversations: Focus on understanding their pains, not pitching solutions. What jobs are they trying to get done? Where’s the friction?

• Behaviour Over Opinions: Look beyond what people say to what they actually do; usage patterns, churn signals, and real-world behaviours.

• Rapid Iteration: Test assumptions quickly. Don’t wait for perfection; validate the core value proposition fast!

Common Mistake:
Trying to “fix” growth with more features when the core value prop hasn’t been validated. The problem isn’t feature gaps, it’s relevance gaps.

2. Product–Channel Fit

📌 Does Your Product Thrive in Your Chosen Channels?

Symptoms of Misalignment:

• Channels that don’t scale

• Poor conversion rates despite strong traffic

• High customer acquisition costs (CAC)

The Diagnostic Lens:
“Is our product designed to succeed in the channels we’re using?”

It’s not enough to have a great product—you need the right channels to reach the right audience effectively. If your product doesn’t align with the dynamics of the channel (e.g., trying to sell a complex enterprise solution through self-serve ads), growth will stall. 

As Balfour puts it, “Products are built to fit with channels. Channels do not mould to products.” The reason for this is simple: we do not define the rules of the channel. The channel defines the rules of the channel. e.g. Google controls search rankings, the structure of Ai search results and how Ads are shown.

Common Mistake: 
Blaming the marketing team when the issue is actually a mismatch between the product and the channel is a common mistake. But even when Product–Channel Fit is achieved, it’s not static; it evolves. A strong fit today can weaken as channels shift, new platforms emerge, or algorithms change.

For example, AI-driven assistants like ChatGPT are changing how people discover information, reducing reliance on traditional SEO. At the same time, the resurgence of podcasts has provided brands with a direct and immersive way to build trust—something that other advertising formats often struggle to achieve.

3. Channel–Model Fit

📌 Can our existing Business Model sustain growth through this channel?

Symptoms of Misalignment:

• Channels that work at small scale but break down as you grow e.g. PPC Ads

• Spending too much to acquire customers relative to the revenue they generate (high CAC / low ARPU and/or Lifetime-Value)

• Revenue growth without target profitability

The Diagnostic Lens:
“Can our business model support the cost structure of our chosen growth channels?” e.g. can you actually afford to hire a direct sales team for your enterprise product?

Even if you’ve found a channel that drives acquisition, it’s useless if your unit economics don’t hold up.

Are you spending more to acquire customers than they’re worth? Can your model support paid channels long-term, or are you reliant on unsustainable growth tactics?

Common Mistake:
Assuming that throwing more budget at a channel will fix scaling issues when the real problem is economic viability. Andrew Chen covers this topic perfectly in his Essay entitled "How startups die from their addiction to paid marketing".

4. Model–Market Fit

📌 Does Your Business Model Align with How the Market wants to buy?

Symptoms of Misalignment:

• Revenue growth that doesn’t translate into profitability

• Inconsistent growth across different market segments

• Friction in the sales process

The Diagnostic Lens:
“Is our business model aligned with how the market/ category wants to buy and pay?”

Put simply, your business model needs to evolve with the market. Are you pricing in a way that reflects the value customers perceive? Does your sales process match how your target audience prefers to buy?

Common Mistake:
Clinging to a pricing plan or sales model that worked early on, but no longer fits the evolving market dynamics.

How to Use the 4 Fits to Diagnose Growth Limiters

When growth stalls, resist the urge to jump straight into solutions.

Step back and ask:

• Where is the friction really coming from?

• Are we misdiagnosing a channel problem as a product issue - or vice versa?

• What are customers telling us? What are we really missing?

Consider running a quick diagnostic:

1. Identify the most visible symptom (e.g., low conversion, poor retention).

2. Trace it back to the underlying fit - don’t assume the surface issue is the root cause.

3. Validate with both experiments and customer insights before taking any major action.

Final Thoughts

Growth challenges are rarely solved by working harder; they’re solved by diagnosing smarter. The 4 Fits framework helps you step back, identify the real friction points, and focus your efforts where they’ll have the biggest impact.

Good luck!

Peter

P.S. If you made it this far—well done! I’m curious, which of the 4 Fits feels like your biggest challenge? Hit reply—I’d love to hear from you.

P.P.S. Had the chance to give a talk on GTM in Edinburgh this week. I didn't dive this deep during the session, so for those of you who attended, I hope this gives you some extra ideas to explore!