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Measurement26 August 20265 min read

The four numbers that tell you growth is stalling

Most ecommerce reporting is too detailed to make a decision with. Four numbers, read together, tell you whether the business is genuinely growing or simply spending more to stand still.

Boards rarely lack ecommerce data. They lack a small set of numbers that everyone agrees means something. When reporting runs to forty slides, the interesting movement is usually in the four that nobody put on the same page.

1. Blended contribution, not channel ROAS

Revenue after cost of goods, fulfilment and total marketing investment — for the whole business, in one line. Channel-level return can improve while this falls, which is the single most common way a growth problem stays invisible for two quarters.

2. Cost to acquire a new customer

Total marketing investment divided by genuinely new customers. Not blended CAC across a repeat-heavy base, which flatters efficiency whenever retention is doing the work. If this rises while contribution is flat, you are buying volume at the expense of margin.

3. Repeat rate within a fixed window

Share of customers who buy again inside a window that matches your real purchase cycle — 90 days for consumables, twelve to eighteen months for considered categories. Lifetime value models hide too many assumptions to argue with; a fixed-window repeat rate does not.

4. Non-branded demand

Branded search and direct traffic measure the demand you already created. Non-branded discovery — organic, assistant surfaces, marketplaces, comparison — measures whether you are still reaching people who do not yet know you. When it flattens, growth becomes a harvesting exercise with a ceiling.

Every stalled ecommerce business we look at was reporting healthy numbers. They were the wrong four.

How to read them together

  • Contribution flat, new customer cost rising: an acquisition economics problem, not a creative one.
  • Contribution rising, non-branded demand flat: you are harvesting; the ceiling arrives in two to four quarters.
  • New customer cost stable, repeat rate falling: a product, merchandising or lifecycle problem being paid for by paid media.
  • All four flat while activity increases: a prioritisation problem, and the cheapest one to fix.

None of this requires new tooling. It requires agreeing on four definitions and holding them constant for long enough that a trend means something.

Takeaways

  • Four numbers beat forty slides for making decisions
  • Blended contribution exposes what channel ROAS hides
  • Non-branded demand is the earliest warning of a growth ceiling

Want an independent read on your four numbers?

The Growth Diagnostic is a senior commercial review of the whole growth system, ending in a prioritised 90-day and 12-month plan.