# We showed 8 real Facebook ads to 120 simulated buyers. It ranked them backwards, and still found the leak. > Source: > Published: 2026-10-25 04:34:50+00:00 Simulation tools love to show the run where they were right. This is a run where one was wrong, and why it was still worth doing. csca.ai sells prep for the CSCA exam (the test for studying in China) to students and parents in South and Southeast Asia. They ran 11 Facebook ads for a free mock test across Nepal, Indonesia, Bangladesh, Vietnam and Sri Lanka, and let us use the real results. **Real results (Meta Ads Manager):** $56.05 spent, 274,557 impressions, 4,466 clicks, 1,500 landing page views, 16 sign-ups. Then we gave MarketMirror the 8 that got most of the budget, plus a brief, **without the results**. It built 120 simulated students and parents (8 audiences × 15 people, each with a short life interview), put the ads in realistic Facebook feeds three times over with different random seeds, and ran a survey on the sign-up offer. We compared the simulated click ranking with the real one. Rank correlation: **-0.84**. That's not "a bit off", that's almost backwards. The simulation's favourite ad was the Nepal broad audience; the real winner was the Indonesia parents ad at 2.32% CTR. If you'd used it to pick which ad gets the budget, it would have pointed you the wrong way. We'd rather say that out loud than hide the run. Look at the real funnel again: 1,500 people reached the page and 16 signed up. About **1 in 100**. The simulated buyers had already said why, in their own words and their own languages: "Gratis tapi minta password lagi? Jangan." (Free, but asking for a password again? No way.) *(Indonesia)* "Phone number dhele spam asbhe." (Give them my number and the spam starts.) *(Bangladesh)* "Free sign-up? They want my phone and email. Harvesting data for sure." *(Nepal)* In the survey, trust ("looks like a scam") was the top blocker for 56% of the simulated people, and privacy for 28%. The real sign-up form asks for full name, email, phone number, country and a password, for a *free* test. The ad wasn't the main problem. The page after it was. From the real ad data plus the run, MarketMirror's `ideas` step wrote five next tests. Two of them: These are proposals, not results. The point is the order: fix the page before buying more clicks. `backtest` and `calibrate` for exactly this.) MarketMirror is open source (AGPL-3.0) and runs from Claude Code, Codex, Cursor, Gemini or any MCP agent. 👉 **[https://github.com/DarkWorldCoder/market-mirror](https://github.com/DarkWorldCoder/market-mirror)**: if it saves you one bad launch, a ⭐ helps other people find it. *Real ad results shared with csca.ai's permission. Simulated buyers are synthetic; their quotes are labelled. Written with help from an AI assistant; every number was checked against the saved data.*