# The Marketing Economist

By Adela Mincea. Marketing and paid media through an economics lens. What's working, what's leaking, and why. Once a month, free by email.

## Start here
- [The ROAS your margin demands, in one table](https://adelamincea.com/insights/break-even-roas): Break-even ROAS is 1 divided by the margin you actually keep. At 25% margin you need 4x just to stand still. Add 20% returns and you need 5x.
- [Your marketing report proves correlation, and that is all it proves](https://adelamincea.com/insights/correlation-causation): The campaign ran. Sales went up. The report says the campaign drove the sales. It doesn't. It shows they happened at the same time. The difference between correlation and causation is the difference between a budget decision and a guess.
- [847 search terms. 12 converting. What that tells you about your Google Ads account.](https://adelamincea.com/insights/search-term-waste): 847 search terms triggered the ads. 12 converted. The other 835 spent $2,800 without a single recorded sale. This is what Google Ads waste looks like, and how to tell it from noise.

## All pieces (10)
- 24 September 2026 · [The ROAS your margin demands, in one table](https://adelamincea.com/insights/break-even-roas) · Economics, Ads: The same ROAS can make one business money and quietly cost another. The difference is gross margin and returns, and it fits in one table.
- 26 April 2026 · [What is agentic commerce and how AI assistants pick products](https://adelamincea.com/insights/agentic-commerce) · AI, Marketing: Shoppers are asking ChatGPT what to buy. Here is how AI assistants pick which products to recommend, and what e-commerce stores need to do to be selectable.
- 23 April 2026 · [Your marketing report proves correlation, and that is all it proves](https://adelamincea.com/insights/correlation-causation) · Measurement: The campaign ran. Sales went up. The report says the campaign drove the sales. It doesn't. It shows they happened at the same time. The difference between correlation and causation is the difference between a budget decision and a guess.
- 16 April 2026 · [The average that's destroying your marketing decisions](https://adelamincea.com/insights/blended-roas) · Measurement, Economics: A blended ROAS of 4.2x sounds healthy. It is also hiding a campaign at 11x and a campaign at 1.1x. Budget follows the average. Raise budgets across the board and the 1.1x grows alongside the 11x. The average looks stable. The economics deteriorate.
- 12 April 2026 · [ROAS is a revenue metric. Your business runs on margin.](https://adelamincea.com/insights/roas-and-margin) · Economics: A ROAS target calculated without reference to your actual gross margin only feels like a performance benchmark. The calculation is straightforward. It rarely gets run.
- 24 March 2026 · [The price you set is a trust signal](https://adelamincea.com/insights/price-signal) · Marketing, Economics: Price communicates quality before a customer evaluates your product. Many businesses treat pricing as margin math. It is also trust architecture.
- 11 March 2026 · [847 search terms. 12 converting. What that tells you about your Google Ads account.](https://adelamincea.com/insights/search-term-waste) · Ads: 847 search terms triggered the ads. 12 converted. The other 835 spent $2,800 without a single recorded sale. This is what Google Ads waste looks like, and how to tell it from noise.
- 4 March 2026 · [The number nobody looks at in your Google Ads report](https://adelamincea.com/insights/landing-page-conversion-rate) · Marketing, Ads: Your Google Ads report leads with impressions, clicks, and click-through rate. The number that tells you whether the money is working, landing page conversion rate, is the one nobody looks at.
- 11 February 2026 · [Google Ads can't save a product nobody is searching for](https://adelamincea.com/insights/search-demand) · Marketing, Ads: Google Ads can only answer demand that already exists. If nobody is searching for your product, paid search can't help. Here's how to check before spending more.
- 4 February 2026 · [The hidden problem behind campaigns that look profitable](https://adelamincea.com/insights/incrementality) · Measurement: Many campaigns look profitable because attribution credits them with sales they did not cause. Incrementality testing reveals what your ads are genuinely contributing versus what would have happened anyway.

Plain text of any piece: add /md to its address. Source: https://adelamincea.com/insights