Methodology
Advert Lumen has two layers. A history-informed baseline predicts your account's metrics from its own history, shrunk toward industry priors where history is thin. A synthetic panel, behind a flag until it is validated, judges how each creative compares with your own past ads. The language model never emits a click-through rate: personas write reactions, and the text is scored against fixed anchor statements.
A number is shown only where a leakage-free evaluation shows it beats a plain historical baseline. Otherwise Advert Lumen shows your account history, a generated review, a comparison that admits ties, and a correctly sized live test.
The metric contract
Every rate Advert Lumen predicts, stores or scores is defined once. Below the eligibility threshold the answer is “insufficient evidence”.
| Objective | Metric | Numerator / denominator | Horizon | Eligibility |
|---|---|---|---|---|
| leads | Link CTR | inline_link_clicks / impressions | First 7 full days of delivery | 5,000 impressions |
| leads | CPM | spend × 1000 / impressions | First 7 full days of delivery | 5,000 impressions |
| leads | CPC | spend / inline_link_clicks | 7 days | 100 link clicks |
| traffic | Link CTR | inline_link_clicks / impressions | First 7 full days of delivery | 5,000 impressions |
| traffic | CPM | spend × 1000 / impressions | First 7 full days of delivery | 5,000 impressions |
| traffic | CPC | spend / inline_link_clicks | 7 days | 100 link clicks |
| sales | Link CTR | inline_link_clicks / impressions | First 7 full days of delivery | 5,000 impressions |
| sales | CPM | spend × 1000 / impressions | First 7 full days of delivery | 5,000 impressions |
| sales | CPC | spend / inline_link_clicks | 7 days | 100 link clicks |
| leads | Lead conversion rate | leads (configured lead action) / inline_link_clicks | 7 days of delivery plus the attribution window | 30 conversions, a configured conversion action |
| leads | Cost per lead | spend / leads | 7 days of delivery plus the attribution window | 30 conversions, a configured conversion action |
| sales | Purchase conversion rate | purchases / inline_link_clicks | 7 days plus attribution | 50 conversions, a configured conversion action |
| sales | Cost per purchase | spend / purchases | 7 days plus attribution | 50 conversions, a configured conversion action |
| sales | ROAS | purchase value / spend | 7 days plus attribution | 50 conversions, a configured conversion action |
Cold-start priors (Leads)
Used only when an account has no history in a cell, as wide priors on primitive metrics. Published cost medians are sanity bounds and never enter the calculation.
| Metric | Prior mean | Source |
|---|---|---|
| Link CTR | 2.70% | WordStream/LocaliQ 2026 via Coupler.io (https://blog.coupler.io/facebook-ads-statistics/) |
| Lead conversion rate | 8.54% | WordStream/LocaliQ 2026 via Coupler.io (https://blog.coupler.io/facebook-ads-statistics/) |
- Published cost medians are sanity bounds only; they never enter the Monte Carlo.