Rewarded placement eCPM shock: bid adjustment worksheet
Illustrative worksheet showing how a mediation eCPM shock changes hybrid ROAS and suggested bid adjustment. Floor/rate mechanics cited from Unity LevelPlay mediation management.
Mediation eCPM swings change hybrid ROAS overnight. This sheet separates an observed eCPM shock (reader input) from the bid adjustment you choose, and cites mediation floor/rate mechanics so the shock is not treated as creative failure.
Mediation lever
Unity LevelPlay mediation management documents that operators can set a floor price so bidding networks below the floor are excluded from the auction, and can assign manual rates that prioritise waterfall instances (the rate is for prioritisation and is not sent back as reported revenue). AdMob rewarded ads define the rewarded format that often sits at the top of hybrid IAA mix.
Synthetic worked example
| Input | Value | Notes |
|---|---|---|
| Baseline rewarded eCPM | 10.00 | Synthetic |
| Shocked rewarded eCPM | 6.50 | Synthetic (−35%) |
| IAA share of D7 revenue | 0.55 | Synthetic reader mix |
| Baseline D7 ROAS | 1.20 | Synthetic |
| Target D7 ROAS | 1.20 | Hold constant |
Implied revenue index after shock ≈ 1 − IAA_share × (1 − eCPM_ratio) = 1 − 0.55 × (1 − 0.65) = 0.8075.
Bid multiplier to hold ROAS ≈ 0.8075 if spend scales linearly with bid (teaching assumption only).
| Output | Worked-example result |
|---|---|
| eCPM ratio | 0.6500 |
| Revenue index | 0.8075 |
| Bid multiplier to hold ROAS | 0.8075 |
Facts versus limits
| Field | Evidence |
|---|---|
| Floor excludes sub-floor bids | Unity LevelPlay mediation management |
| Manual rate ≠ reported revenue | Same page |
| Linear bid↔spend assumption | Teaching only — not a network guarantee |
| Observed shock | None — reader input |
