With long sales cycles, waiting for closed revenue to judge a campaign means you're always looking at decisions made months ago — too slow to actually steer anything. The practical fix is leaning on leading indicators that correlate with eventual revenue: qualified pipeline created, opportunity velocity through each stage, and cohort-based tracking that follows a specific month's leads all the way through instead of comparing unrelated monthly snapshots.
Pair that with periodic multi-touch attribution reviews to catch which early-funnel activity actually shows up in deals that close many months later — a single-touch, last-click view will systematically undercredit early content and brand-building work in long-cycle businesses.