UTM parameters and default channel grouping
Analytics tools sort traffic into channel groups (Paid Search, Organic Social, Email, Referral, Other) using rules built mostly on utm_medium. Choose the wrong medium and good traffic falls into 'Other' or the wrong channel. This page explains how the mapping works and the medium values that keep channels correct.
How the mapping works
Default channel grouping is a set of ordered rules. Most rules key off utm_medium (sometimes combined with utm_source). For example, a medium of cpc or ppc with a search source maps to Paid Search; a medium of email maps to Email; a social medium maps to Organic or Paid Social depending on the rule.
When no rule matches, the traffic falls into Other/Unassigned — usually because the medium is a value the rules do not anticipate.
- utm_medium=email → Email
- utm_medium=cpc / ppc / paidsearch → Paid Search
- utm_medium=paid-social → Paid Social
- utm_medium=affiliate → may need a custom rule
Why mediums end up in Other
Free-text mediums (newsletter-blast, fb-promo, social_paid) often do not match any rule and land in Other. The fix is to standardize utm_medium to the small set of values your tool's channel rules recognize, and add custom channel rules only where you genuinely need a channel the defaults lack (e.g. affiliate, native).
Worked example: change utm_medium=newsletter-blast to utm_medium=email so it maps to the Email channel.
Custom channels and consistency
If you run channels the defaults do not cover (native, retargeting, partner), define custom channel rules and a fixed medium for each, then never deviate. Consistency between your medium vocabulary and your channel rules is what keeps reports stable.
How it appears in analytics and logs
Traffic landing in '(Other)' or 'Unassigned' almost always means a utm_medium the channel rules do not recognize. Aligning the medium to the expected vocabulary moves it to the right channel.
Diagnostic use case
Pick utm_medium values that map cleanly into the right default channel group, so campaigns appear under Paid, Email, or Social rather than Other.
What WebmasterID can help detect
WebmasterID attributes traffic by the source/medium you set, so consistent, channel-aligned mediums produce reports that match how you think about channels.
Common mistakes
- Using free-text mediums that fall into Other/Unassigned.
- Putting the platform name in utm_medium instead of the channel type.
- Creating custom channels without fixing a single medium per channel.
- Changing medium vocabulary without updating channel rules.
Privacy and accuracy notes
Channel grouping uses the medium/source labels you set, not visitor data. Keep those labels generic and free of any personal information.
Frequently asked questions
- Why is my campaign showing as (Other)?
- Its utm_medium does not match any channel-grouping rule. Standardize the medium to a recognized value (like email or cpc) or add a custom channel rule for it.
Related pages
- UTM casing and consistency
Casing is the single most common UTM data bug. Because tools match values as exact strings, utm_source=Reddit and reddit are two separate rows, so one campaign quietly fragments. This page makes the lowercase rule concrete and shows how to deepen it into real consistency.
- How to audit your UTM parameters
Over time, UTM values drift — Facebook and facebook, email and Email, newsletter and news — and split one channel into several report lines. A periodic UTM audit finds and consolidates that drift. This page describes a repeatable audit method you can run from your analytics export.
- UTM naming conventions that survive reporting
Most UTM data problems are naming problems. Because tools treat utm_source=Reddit and reddit as different values, inconsistent casing and spelling fragment one campaign across many rows. This page gives a convention — lowercase, hyphenated, documented allow-list — that keeps reports clean.
- Attribution analytics
See campaigns mapped to the channels you expect.
Sources and verification notes
- Google Analytics Help — Default channel groupHow utm_medium/source map into channels and what lands in Unassigned.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.