GAM reporting vs log-level data: what you can't see is costing you

GAM reporting vs log-level data: what you can't see is costing you
Heard: ops teams optimize entirely off GAM's UI and never pull the auction logs where the leaks actually live.
— GAM reports: aggregate, fast, fine for trafficking and pacing.
— Data Transfer / log-level files: per-impression auction outcomes — the ONLY way to catch timeout losses, no-bid patterns, and SSP underbidding.
— Prebid Analytics adapters cover the bid layer; GAM Data Transfer covers the served layer. You need both stitched.
Impact: If a partner looks weak in GAM, prove it in log-level before you cut them — UI lies by aggregation. (sourced)