Revenue and ROI
If it doesn't move revenue, it doesn't matter.
I've managed $30M+ in ad spend at 350 to 400% ROAS, and I start every engagement with the money math, not the media plan. Deal value, close rate, cost per acquisition. Then I work backward to the leads and budget that hit the number.
That math also sets honest expectations. At the agency, setting cost-per-lead expectations with clients up front took average client retention from 4 to 5 months to about 9.
Sometimes the revenue leak isn't in the ads at all. One client blamed marketing for slow sales. The calls showed the real problem: their phone team was hanging up on leads the campaigns had already paid for. Fixing the handoff mattered more than any bid change.