Attribution
Acquisition
Also called traffic acquisition.
Acquisition is the report family that explains how sessions arrived at your site. It groups arrivals by channel, source, and campaign.
How it is measured
Each session is labeled at its start from the referrer, a campaign tag, or neither. Those labels roll up into channels and are summed per session, per new visitor, or per conversion.
Read acquisition next to behavior, not alone. A channel with many sessions and no engagement is a different story from a small one that converts. A cookieless tool labels each session from what is visible at that visit, so it will not credit a source from a visit last month.
Worked example
A candle maker opens the acquisition report for October. Organic search shows 5,400 sessions, email 1,640, social 2,300, and referral 640. Orders per channel are 74, 112, 31, and 46.
The big social number turns out to be mostly one giveaway post. Email, with a third of the sessions, produced the most orders. The maker moves the next holiday budget to the email list and a gift-guide landing page.
How it differs
Acquisition describes how people got to the site. A channel grouping is the rule that puts the sources into buckets. One reports; the other defines the buckets.
Common errors
Judging channels by sessions alone. Reading last month's labels as this month's. Ignoring untagged traffic. Treating all referral as one source. Comparing channels with different tracking quality.
In practice
Open the report with a conversion column and sort by it, not by sessions. Check which sources have no tag. Fix the biggest unlabeled bucket first.