Growth Model: Why Most Businesses Are Measuring the Wrong Thing

A growth model is a structured framework that maps how a business acquires customers, retains them, and generates revenue, with each stage connected so you can see where growth is actually coming from and where it is leaking. Done properly, it forces you to be honest about the mechanics of your business rather than optimistic about your marketing.

Most businesses do not have one. They have targets, dashboards, and a collection of channel metrics that feel like a growth model but are not. The difference matters more than most marketing teams want to admit.

If you are working through how growth strategy fits into your wider commercial planning, the full picture is covered in the Go-To-Market and Growth Strategy hub, which brings together the frameworks, decisions, and sequencing that make growth models operational rather than theoretical.

What Is a Growth Model and Why Does It Matter?

A growth model is a representation of the causal relationships that drive revenue in your business. It shows how inputs, things like marketing spend, sales activity, product changes, and customer service quality, translate into outputs like revenue, margin, and customer lifetime value. It connects the levers you can pull to the outcomes you care about.

This sounds straightforward. In practice, most businesses substitute a growth model with a collection of activity metrics that are easier to measure but harder to connect to actual growth. Impressions, click-through rates, cost per lead, conversion rates by channel: these are useful data points, but they do not constitute a model. A model requires you to understand the relationships between those numbers, not just track them in parallel.

The distinction matters because when growth slows, which it always does eventually, you need to know why. If you have a genuine growth model, you can isolate the variable that changed. If you have a dashboard, you have a set of numbers that have all moved and no reliable way to determine causation.

I have sat in enough quarterly business reviews, across enough sectors, to know that most commercial teams are better at describing what happened than explaining it. Revenue is up 12 percent. Paid search performed well. The new campaign drove strong awareness metrics. These are observations. They are not explanations. A growth model forces you to build the explanation before the quarter ends, not retrospectively after the numbers come in.

The Three Structural Problems That Make Most Growth Models Useless

Before getting into how to build a growth model that works, it is worth being direct about why most attempts fail. There are three structural problems that recur regardless of industry, company size, or how sophisticated the marketing team thinks it is.

They are built around available data, not causal drivers

The first problem is that most growth models are built around what can be measured easily rather than what actually drives growth. Digital channels produce a lot of data. That data is accessible, attributable, and reportable. So models get built around it. Offline activity, word of mouth, brand effects, and long-term customer value get underweighted or excluded because they are harder to quantify.

The result is a model that tells you a lot about your paid digital channels and relatively little about your business. I have seen this pattern in consumer brands where the majority of volume was driven by in-store visibility and category management, but the growth model was almost entirely built around e-commerce and paid social metrics. The model was technically accurate for the channels it covered. It was commercially misleading for the business it was supposed to represent.

They conflate demand capture with demand creation

The second problem is one I have thought about a lot over the past decade. Earlier in my career, I overvalued lower-funnel performance channels. The metrics were clean, the attribution was tidy, and the results looked compelling. What I came to understand, slowly and through enough contradictory evidence, is that much of what performance marketing gets credited for was going to happen anyway. Someone who has already decided to buy your product and searches for your brand name is not being won by your paid search ad. You are just paying to be visible at the moment of a decision that was already made.

Think of it like a clothes shop. A customer who has already tried something on is dramatically more likely to buy it than someone who has not. If a sales assistant intercepts them at the till and takes the credit for the sale, the metric looks great. The model, however, is wrong. Growth requires reaching new audiences and creating new demand, not just capturing the intent that already exists. A growth model that does not distinguish between these two things will consistently overstate the contribution of performance channels and underinvest in the activity that actually builds the top of the funnel.

The Forrester intelligent growth model addresses this directly, drawing a line between growth that comes from capturing existing demand and growth that requires creating new demand. It is a useful frame, even if the execution varies considerably by category.

They model acquisition in isolation from retention

The third structural problem is that most growth models treat acquisition and retention as separate workstreams rather than connected variables in the same equation. This produces a situation where a business can appear to be growing on acquisition metrics while quietly deteriorating on retention, and the two never get reconciled until the revenue number starts to soften.

A business that acquires 1,000 new customers a month while losing 900 existing ones is not growing in any meaningful sense. But if the acquisition team and the retention team are reporting into different parts of the business with different metrics, the problem can remain invisible for longer than it should. A growth model has to hold both variables simultaneously and show how they interact.

How to Build a Growth Model That Is Actually Useful

Building a growth model is not a technical exercise. It is a thinking exercise that happens to produce a document or a spreadsheet at the end of it. The sequence matters.

Start with the revenue equation, not the channel plan

Begin by writing down the simplest possible version of how your business generates revenue. For most businesses, this is some version of: number of customers multiplied by average transaction value multiplied by purchase frequency. For subscription businesses, it is something like: total subscribers multiplied by average revenue per user, minus churn. For marketplaces, it is different again.

The point is to start with the commercial reality of the business, not with the marketing channels. Once you have the revenue equation, you can work backwards to identify which variables have the most leverage. A 10 percent improvement in retention might be worth three times as much as a 10 percent improvement in acquisition volume, depending on the unit economics. You will not know that until you have the equation in front of you.

BCG’s work on commercial transformation makes a similar point: sustainable growth comes from understanding the commercial levers that drive value, not from optimising channel performance in isolation from the wider business model.

Map the customer experience as a funnel with conversion rates at each stage

Once you have the revenue equation, build a funnel that shows how customers move from first awareness through to purchase and, critically, through to repeat purchase or retention. At each stage, attach a conversion rate. These do not need to be precise to three decimal places. They need to be honest approximations that reflect reality.

This is where tools like Hotjar and other behavioural analytics platforms become genuinely useful, not as dashboards to report from, but as diagnostic tools to understand where the funnel is leaking. The distinction is important. Most teams use analytics tools to report what happened. A growth model requires you to use them to understand why it happened and what you can change.

I spent a period working with a B2B business where the sales team was convinced the problem was lead volume. The growth model told a different story. Lead volume was fine. The conversion rate between qualified lead and first meeting was the problem, and that was a sales process issue, not a marketing one. Without the model, the business would have spent money generating more leads into a funnel that was already leaking badly at stage two.

Identify the one or two variables with the most leverage

A growth model is not useful if it produces a list of twenty things to improve. The purpose of the model is to identify the variables where a change in performance produces a disproportionate improvement in the output. Usually there are one or two of these. Everything else is noise by comparison.

This requires running the numbers. Take your funnel, change one variable by a realistic amount, and see what happens to the revenue output. Then do the same for every other variable. The ones that produce the largest revenue impact for the smallest input change are your growth levers. These are where your attention and your budget should be concentrated.

For most businesses, this exercise produces a result that is either obvious in retrospect or genuinely surprising. Either way, it is more useful than a strategic planning session that produces a list of priorities without any quantification of their relative impact.

Growth Loops vs. Funnels: Which Model Fits Your Business?

There is a useful distinction between funnel-based growth models and loop-based growth models that is worth understanding before you decide which structure to use.

Funnel models are linear. Traffic enters at the top, moves through stages, and exits as revenue. They are appropriate for businesses where each customer acquisition is largely independent: the fact that you acquired customer A does not meaningfully affect your ability to acquire customer B. Most traditional businesses and many B2B businesses operate on funnel logic.

Loop models are compounding. Each customer acquired creates the conditions for acquiring the next one, either through referral, content creation, network effects, or marketplace liquidity. Businesses built on loop mechanics grow differently from funnel businesses. The early growth is slower, but once the loop is working, the marginal cost of acquisition falls as volume increases.

The practical question is which model fits your business. Most businesses are primarily funnel businesses with some loop characteristics. A few, particularly marketplaces, social platforms, and referral-driven services, are genuinely loop businesses. Misidentifying which one you are leads to misallocating resources. Funnel businesses that try to build loop mechanics before they have the volume to sustain them tend to waste a lot of time and money on referral programmes that produce negligible results.

If you want to explore growth hacking tools and techniques that support both model types, Semrush’s overview of growth hacking tools covers the practical toolkit well, though the tools are only as useful as the model that directs how you use them.

The Role of Agility in Executing a Growth Model

A growth model is a planning tool, not a fixed plan. The distinction matters because markets change, competitive dynamics shift, and customer behaviour does not hold still. A model that was accurate twelve months ago may not be accurate today, and one of the disciplines of running a growth model well is revisiting the assumptions regularly rather than treating the initial build as permanent.

This is where agility becomes a structural advantage rather than just a process preference. BCG’s research on scaling agile identifies the ability to test, learn, and adjust quickly as a core component of sustainable growth, not just a methodology for software teams. The same principle applies to growth models. Build in regular review cycles, define what would cause you to revise a core assumption, and treat the model as a living document rather than an annual planning artefact.

When I was growing an agency from around twenty people to over one hundred, the growth model we were operating against changed meaningfully three or four times over that period. The revenue equation stayed the same: headcount times utilisation times rate. But the levers that drove each of those variables shifted as the business scaled. Early on, the primary lever was winning new clients. Later, it became retaining and growing existing ones. A model that did not reflect that shift would have kept us focused on the wrong thing at exactly the wrong time.

Common Growth Model Mistakes That Senior Marketers Still Make

There are a handful of mistakes that appear consistently across growth models, regardless of how experienced the team building them is.

The first is building the model to justify a decision that has already been made. This is more common than anyone admits. A business decides it wants to expand into a new market or launch a new product, and the growth model gets built retrospectively to support the business case. The inputs get selected to produce the desired output. This is not a growth model. It is a financial presentation with extra steps.

The second is over-engineering the model to the point where it becomes unworkable. I have seen growth models that required a data scientist to update and a two-hour briefing to interpret. Models that complex do not get used in commercial decision-making. They get presented once, filed, and referenced in passing for the rest of the year. A growth model needs to be simple enough that a commercial director can hold the key variables in their head and use them to make decisions in real time.

The third mistake is treating the model as a forecasting tool rather than a diagnostic one. Forecasting is useful, but it is not the primary purpose of a growth model. The primary purpose is to understand the mechanics of your business well enough to intervene effectively when something changes. If your model tells you revenue will be up 15 percent next year but cannot tell you what to do when it comes in at 8 percent, it has not done its job.

For practical examples of how growth mechanics have been applied across different business types, Semrush’s collection of growth hacking examples is worth reviewing, with the caveat that most of the tactics described only work within the context of a coherent model, not as standalone experiments.

There is also a broader pattern worth naming. Many of the most celebrated growth stories are presented as the result of a single clever tactic: a viral referral mechanism, an unconventional channel, a product feature that spread organically. In most cases, the tactic worked because it was deployed against a business with strong underlying unit economics and a clear model of how growth happened. The tactic was the accelerant, not the engine. CrazyEgg’s breakdown of growth hacking makes this point well: the tactics only compound when the fundamentals are already in place.

How to Know When Your Growth Model Is Working

A growth model is working when it changes the decisions your business makes. That is the only meaningful test. If your model produces a document that gets reviewed quarterly and does not alter how budget is allocated, how teams are structured, or how performance is evaluated, it is not functioning as a growth model. It is functioning as a reporting exercise.

Practically, a working growth model should be able to answer a small number of questions at any given time. Which lever has the most room to improve? Where is the funnel losing the most value? What is the unit economics impact of acquiring a customer through channel A versus channel B? What would need to be true for the business to hit its growth target without increasing marketing spend?

If your team can answer those questions from the model without having to go away and build a new analysis, the model is working. If every question requires a fresh piece of analysis, the model is not embedded in how the business operates.

I have judged the Effie Awards, which are explicitly about marketing effectiveness rather than creative execution. One of the things that separates the strong entries from the weaker ones is not the quality of the creative work. It is whether the team can demonstrate a clear understanding of the mechanism by which their marketing drove the business outcome. That understanding comes from having a growth model, even if nobody calls it that. The teams that win tend to be the ones who knew exactly which variable they were trying to move and why moving it would matter commercially.

If you want to go deeper on how growth models connect to broader commercial strategy, the Go-To-Market and Growth Strategy hub covers the full range of frameworks and decisions that sit around and beneath the growth model itself, from market prioritisation through to channel sequencing and performance measurement.

About the Author

Keith Lacy is a marketing strategist and former agency CEO with 20+ years of experience across agency leadership, performance marketing, and commercial strategy. He writes The Marketing Juice to cut through the noise and share what works.

Frequently Asked Questions