Six New Numbers – 2
- Growth & Profit Balance (Rule of 40): Balancing Speed and Sustainability
The Rule of 40 provides an elegant solution to the growth-versus-profitability dilemma that plagues many eCommerce businesses. By stipulating that a healthy business’s combined revenue growth rate and profit margin should exceed 40%, it creates a flexible framework that accommodates different strategic phases while maintaining fiscal discipline.
This metric acknowledges that companies may legitimately prioritise growth over immediate profitability, but not without limits. A business growing at 50% annually can run at a 10% loss and still meet the Rule of 40 standard, while a mature business growing at 15% should generate at least 25% profit margins.
What makes the Rule of 40 particularly valuable for eCommerce is its ability to counterbalance the industry’s frequent over-emphasis on growth at all costs. By incorporating this metric into regular reporting, businesses create a natural brake against unsustainable practices like excessive discounting, over-reliance on paid acquisition, or margin-eroding free shipping policies.
- LTV/CAC Ratio: The Ultimate Business Health Indicator
The LTV/CAC ratio stands as the definitive measure of business model viability. While most businesses track these metrics separately, their relationship tells the true story. A healthy business maintains a ratio of at least 3:1, meaning each customer acquired delivers three times their acquisition cost in lifetime value.
The power of this metric lies in its comprehensive nature. It incorporates acquisition efficiency, retention success, pricing strategy, and margin structure into a single number. When segmented by acquisition channel, product category, or customer cohort, it reveals which parts of your business create genuine value and which destroy it.
Unlike simplistic metrics like conversion rate or CPC, the LTV/CAC ratio forces long-term thinking. It prevents the common trap of celebrating a low CAC that comes at the expense of customer quality, or a high LTV achieved through excessive acquisition spending. It answers the fundamental question: “Is this business model structurally sound?”
- Existing Revenue Ratio: The Retention Reality Check
The ratio between revenue from existing customers versus new customers provides a straightforward assessment of retention effectiveness. While most eCommerce businesses obsess over new customer acquisition, this metric reveals whether those expensive new customers actually stick around.
A healthy business typically generates 60-70% of its revenue from existing customers. When this percentage drops below 50%, it often indicates that the business is caught in a “leaky bucket” syndrome—acquiring customers at great expense who don’t return for subsequent purchases.
This metric serves as a powerful reality check on customer experience. No amount of marketing spin can obscure a declining existing-to-new revenue ratio, which represents the unvarnished verdict of customers voting with their wallets. It answers the critical question: “Are we creating relationships or just transactions?”
- Segmentation Balance (BRTN Split): Strategic Customer Segmentation
The BRTN framework (Best-Rest-Test-Next) revolutionises how eCommerce businesses view their customer base. Unlike traditional RFM segmentation, which creates complex matrices, BRTN provides a clear, actionable breakdown:
- Best: Top 20% of customers who generate 60-80% of revenue and 200% of profits
- Rest: Middle 40-50% showing declining engagement who need revitalisation
- Test: Dormant 30-40% who have gone inactive and require reactivation
- Next: Genuinely new prospects who need conversion and onboarding
Tracking the revenue and customer count distribution across these segments reveals the true health of your customer portfolio. A growing percentage of “Best” customers indicates improving loyalty and engagement. An expanding “Test” segment signals retention problems requiring immediate attention.
The BRTN Split connects analytics directly to strategy, prescribing specific approaches for each segment: Velvet Rope Marketing for Best, personalised engagement for Rest, targeted reactivation for Test, and efficient conversion for Next. This creates clear ownership and accountability within marketing teams.
