UTM parameters: labelling links so the numbers add up

UTM parameters are labels added to the end of a link so that analytics can tell one source of traffic from another. They are simple, free and almost universally mishandled: four people tag the same campaign four ways, and the report shows nine entries for one email. The tagging is not the hard part — agreeing the words is.

The five UTM parameters

• Source: where the click came from, as a platform or publication — a mailing list, a search engine, a partner site.
• Medium: the kind of channel, such as email, social, referral or paid. This is the field people guess at most.
• Campaign: the specific activity, named so that somebody who was not involved can tell what it was.
• Content: which link within the same message or page, used for telling a button apart from a text link.
• Term: the paid keyword, which is rarely needed outside advertising.

A convention that survives colleagues

Decide three rules and write them where links are made: everything lowercase, hyphens rather than spaces or underscores, and a fixed vocabulary for medium. Those three prevent most of the damage, because analytics treats Email, email and e-mail as three different channels and nobody notices until a quarterly report looks wrong. Keep a shared list of the campaign names actually in use, since the alternative is each person inventing a name and no two rows ever aggregating.

Never tag internal links. A UTM on a link between two of your own pages restarts the session attribution, so visitors who came from search get re-attributed to your own newsletter, and the original source disappears. This single mistake invalidates more analytics than any other.

Where tagging goes wrong

1. Inconsistent case and separators, which silently split one campaign into several rows.
2. Medium used as a free text field rather than from a fixed list of four or five values.
3. Tagging internal navigation, which destroys the original attribution.
4. Leaving UTMs on links that get shared onwards, so organic shares are reported as campaign traffic.
5. Forgetting that the parameters are visible in the address bar — never put anything in them you would not show the recipient.
6. Tagging only some channels, which makes the untagged ones appear as direct traffic and flatters nothing.

What they can and cannot tell you

They tell you which link was clicked, and that is all. They do not survive a visitor switching device, they do not attribute the sale somebody made three weeks later from a search, and they say nothing about why. Used honestly they answer one question well — which of the things we sent produced visits — and most disappointment with them comes from expecting a full attribution model from five text fields appended to a URL.

Ettex Web keeps the landing page and the links to it in one place, so the tagged URLs for a campaign live beside the page they point at rather than in somebody's notes. The discipline is the same one that makes any shared vocabulary work: a fixed list of values beats free text every time somebody has to count the result.