First-touch vs last-touch attribution in B2B
First-touch attribution credits the first visit on a buyer's path. Last-touch attribution credits the last click or last event before the meeting or the closed deal.
Those two answers rarely match. First-touch points at the campaign that created the memory. Last-touch points at the channel that caught the form. In a B2B cycle that spans weeks, both can be true on the same journey, and both can be wrong if the underlying events never met.
We already covered what B2B attribution has to connect and where marketing attribution stops. This piece is the model choice teams argue about once the path exists: first-touch versus last-touch.
What does first-touch attribution credit?
First-touch gives 100% of the credit to the earliest event you stored. Usually that is the first website visit: a paid ad, a search result, a newsletter, a ChatGPT citation, or a colleague's link.
It answers a creation question. Which source introduced this account? That is useful when you are funding awareness, category pages, or outbound that starts a journey months before a demo. If you only look at last-touch, those programs look empty.
First-touch fails when the first event is missing or wrong. If the first visit landed in Direct with no referrer, first-touch credits Direct. If the CRM source field is the first form a rep typed in, first-touch never saw the earlier pages. The model is only as honest as the first row on the path.
What does last-touch attribution credit?
Last-touch gives 100% of the credit to the last event before the conversion you care about. For many teams that conversion is a form fill. For a revenue team it should be the meeting that opened the opportunity, or the closed deal.
It answers a harvest question. Which channel was open when the buyer finally acted? Paid search, a retargeting ad, or a sales-assisted calendar link often win that seat. Finance likes last-touch because one row maps to one owner.
Last-touch fails the same way last-click fails. A VP can see an ad in March, read a comparison post in April, and book from branded search in May. Last-touch hands May the whole deal. The ad and the post vanish. You then cut the work that created demand and keep the channel that caught the leftover click.
Why do B2B cycles make the split worse?
A consumer checkout can finish in the same session as the ad. A B2B deal usually takes more than one buyer, more than one visit, and a call that never fires a pixel. The person who first landed is often not the person who booked.
Time stretches the gap. Campaign windows expire. The first touch lives in an old report. The last touch lives in this quarter's CRM. If those two systems do not share a journey, the weekly meeting becomes a fight about whose dashboard is right.
Offline and LLM traffic widen it further. A conference meeting can be the real first event, with no website session behind it. A Claude or Perplexity citation can start a path that later looks like Direct, then branded search. We wrote about how LLM visits vanish into Direct and what view-through keeps on the path. First-touch and last-touch both need those events stored, or they will credit the wrong row.
Where do multi-touch and CAC fit?
Multi-touch is not a third religion that replaces the other two. It is another lens on the same path. First-touch, last-touch, and multi-touch all fail if the visit, the meeting, and the deal never joined. They just fail with different math.
Put the path together first. Then first-touch tells you what created the account. Last-touch tells you what closed the form or the call. Multi-touch spreads credit across the steps in between. You can keep all three views without pretending one of them is the only truth.
CAC is where the model choice becomes a budget decision. Cost per click and cost per form fill are lead costs. Real CAC needs closed customers and the spend that sat on their path. If you only use last-touch, you will fund harvest channels and starve creation. If you only use first-touch, you can overfund the first ad and ignore the work that finished the deal. The useful report shows both, on the same closed-won journeys, next to channel quality and the goal you actually care about.
Google Ads, HubSpot, and Calendly each see a slice of that path. Ads see the click. The CRM sees the contact and the deal. The calendar sees the meeting. None of them is the full journey unless you stitch them.
A check you can run this week
Pick five closed-won deals. For each one, name the first visit and the last event before the meeting that opened the opportunity. Write both down. Then ask whether first-touch, last-touch, and the CRM source field agree.
If they disagree, you are looking at two honest models on incomplete data, or on a path that was never stitched. The fix is not picking a louder model. The fix is connecting the visit, the pages, the meeting, and the closed deal.
You do not need a warehouse to close that gap. One pixel on the site, plus the GTM tools you already run, is enough. You can chat with the data, get an AI recommendation, and receive a daily report in Slack.
Source is built that way. Drop in one pixel and it connects across the tools you already use. Multi-touch, view-through, offline activity, and LLM attribution sit on the same path as a real CAC, a goal, and a read on channel quality.
Customer data is not used to train external models. Source is SOC 2 Type II and ISO 27001 certified.
If you want first-touch and last-touch on the same visit-to-deal path, start at Source. Attribution is broken. So we rebuilt it.