TACoS: paid plus organic efficiency, not just paid RoAS
Incrementality: what paid truly adds versus what would have happened anyway
Sales velocity and elasticity: when spend should flex up or down
Product-level economics: where ads should scale, and where they should not
Channel balance: Amazon PPC versus DSP versus off-Amazon demand capture
Based on margin, conversion rate, and elasticity.
What paid truly adds — not what would have happened anyway.
Incremental revenue per $1K spend