2 resources from Eightx we point founders to, and the questions each answers.
📄 Article
✓ Link checkedFreeBeginner
Why we picked it
If full incrementality testing is more than your team can run right now, blended metrics are the honest shortcut, and this article lays them out cleanly. Blended CAC (total spend divided by all new customers) and MER (total revenue divided by total spend) cannot be gamed by any single platform, because they count every rupee of spend against every real customer. For a small team building outside the big startup hubs, this is the most practical way to stop the platforms from grading their own homework.
Why we picked it
This is a focused, plain-language piece on the exact trap in the question: a low blended CAC that quietly counts customers you never paid to acquire (word of mouth, referrals, your own network). It gives a concrete worked example where blended reads 42 dollars but true paid CAC is 70, and shows how to isolate the paid number using CRM-attributed customers rather than ad-platform counts. A good starting point for pressure-testing whether your economics survive without the promo.
Blended CAC divides total spend by every new customer including free channels, so a founder-led discount or your personal network can make the headline number look far better than the paid engine really is.
To find your true paid CAC, divide full paid spend (media, agency, creative, affiliate) by customers acquired through paid channels, measured at your CRM.
Report both numbers and never compare your blended CAC to a competitor's paid CAC, because the gap is where scaling ads later goes wrong.
