Every catalog has a product that sells constantly, tops the reports, and quietly loses money on every order. Founders rarely notice for months — because every dashboard is sorted by revenue, and revenue is the one number that flatters it.
The hobby test
Take your top SKU by revenue. Now subtract, per unit: COGS, marketplace or payment fees, shipping and packaging, expected returns, and its share of ad spend. What's left is its contribution margin — the money it actually contributes to rent and payroll.
If that number is near zero or negative, congratulations: you don't have a best-seller, you have an expensive hobby with a loyal following.
The usual suspects
- Free shipping on heavy or oversized items — shipping eats the margin before ads even start.
- High-return categories like apparel, where 15–25% of units come back.
- Bundles that discount your hero product into a loss leader you never priced as one.
- Ad spend defending a "top seller" whose margin was 8% before the click cost a thing.
What to do with the losers
You rarely need to kill them. Raise the price and watch the elasticity. Set a minimum order or bundle threshold so shipping averages out. Cut the ad spend and let them sell organically — organic volume at 8% margin beats paid volume at negative margin. Or renegotiate COGS: at scale, a supplier conversation is worth more than a week of CRO work.
Sort by what matters
In Data Doodle, products are ranked by contribution margin by default, not sales. The view usually rearranges your top ten within the first hour of real data — and the expensive hobbies have a way of introducing themselves immediately.