How do you prove marketing ROI when B2B buying journeys involve dozens of touchpoints across months?

B2B attribution is genuinely hard. Buying committees of 6-10 people, 6-18 month cycles, anonymous research phases, dark social, AI-assisted discovery. No attribution model captures all of it cleanly. Accept that upfront. The goal isn't perfect attribution; it's defensible attribution that earns trust with the CFO and sales team.

The attribution frameworks that actually work

First-touch attribution tells you what created awareness. Useful for understanding which channels are introducing your brand to new buyers, but it overvalues top-of-funnel activity.

Last-touch attribution tells you what closed. Useful for sales but actively misleading about marketing's contribution. It credits the final SDR sequence and ignores everything that built the preference.

Multi-touch attribution distributes credit across the journey. More accurate but requires clean data and good tooling. W-shaped (first touch, opportunity creation, and closed-won each get weighted credit) is a practical starting point for most B2B teams.

Pipeline influence tracks which contacts had a marketing touchpoint before or during an opportunity. Often the most credible model for B2B because it doesn't require you to solve for causation, just correlation.

What actually builds CFO trust

Attribution models are necessary but not sufficient. What earns real credibility with the CFO is connecting marketing activity to pipeline outcomes with consistent methodology, quarter over quarter. Pick a model, commit to it, and show the trend. A consistent story about marketing's contribution is more persuasive than a technically perfect attribution model that changes every quarter.

The dark funnel problem

A growing share of B2B buying happens in channels you can't track: AI conversations, private Slack communities, peer recommendations, anonymous website research. The right response isn't to try to instrument all of it. Build brand presence and content authority in those channels and measure the business outcomes, pipeline, win rates, deal velocity, rather than every individual touchpoint.