How to measure campaigns without fooling yourself

Measuring a campaign means answering one question: what did it cost to get a customer and what is that customer worth. Everything else is supporting detail, and much of it is vanity.

I write this because it is the problem I meet most often: twenty-page reports full of impressions and reach, from which you cannot tell whether the campaign made or lost money.

Which metrics matter and which do not?

Metric	Useful?	Why
Cost to acquire a customer	Yes, the main one	It is the business number
Customer value over time	Yes	Defines what you can pay for one
Cost per qualified lead	Yes	Useful while the sale matures
Conversion rate by channel	Yes	Shows where to invest
Clicks and CTR	As diagnosis	They say the ad attracts, not that it sells
Impressions and reach	Almost never	Useful for awareness, not for sales
Followers	No	They do not pay invoices
”Engagement”	No	The easiest number to inflate

The test for whether a metric is useful: would any decision change if it moved 20% up or down? If not, take it out of the report.

Which numbers must you have before launching?

Three, and without them nothing can be judged afterwards:

1. What a customer is worth to you. Average ticket times expected number of purchases.
2. What you are willing to pay to acquire one. Usually a fraction of the above.
3. How many of the people who contact you end up buying. If you do not know, start recording it today.

With those three you can decide in the first week whether a campaign is working. Without them you can only have opinions.

How do you use UTMs without breaking anything?

UTMs are the tags you add to a link so you know where each visit came from. They are simple and they break through carelessness.

Parameter	What for	Example
utm_source	The platform	facebook
utm_medium	The traffic type	cpc
utm_campaign	The campaign	libro-medico-sep2026
utm_content	The specific ad	video-a
utm_term	The keyword	marketing-consultant

Four rules that prevent 90% of problems:

• Lowercase, no accents. Facebook and facebook count as two different sources.
• Always use the same values. Write the convention down and have the whole team follow it.
• Never put UTMs on internal links of your own site. They restart the session and cause traffic to attribute itself.
• Always use utm_content. It is what lets you compare two creatives from the same campaign. Without it you know the campaign worked, but not which ad made it work.

Why do the numbers never match between platforms?

Because each one counts in its own favour and by different rules. It is not your mistake and it does not get fixed.

• Attribution windows differ. Meta may claim a sale that happened days after an ad view; your analytics may not see it that way.
• Each platform claims its own. Meta counts the sales it believes it caused; Google does the same. Add them together and you will have more sales than really happened.
• Blockers and privacy trim browser-side data.

The practical way out: choose one source as the official truth, usually your own sales system, and use the platforms to optimise within each. Trying to make them reconcile is wasted work.

What should the monthly report contain?

One page. Five things:

1. How much was spent, and on which channels.
2. How many leads and how many customers came in.
3. Cost per customer, compared with last month.
4. What was learned, in one sentence.
5. What will change next month.

If the report does not end at point five, it is a statement, not a management tool.

Frequently asked questions

Which campaign metrics are most important? The cost of acquiring a customer and that customer’s value over time. Those two decide whether a campaign is worth running. The rest help diagnose why.

What are vanity metrics? The ones that rise without the business improving: impressions, reach, followers and engagement. Not entirely useless, but they should not lead a report.

Why do Meta and Google Analytics give me different numbers? Because they attribute with different rules and windows, and each platform tends to claim the credit. They will never match. Pick one official source and use the rest to optimise.

What is utm_content for? To know which specific ad produced the result. Without it you can compare campaigns but not two creatives within the same campaign, which is exactly what you need to improve.

How often should I review a campaign? Paid campaigns, every two or three days at first and then weekly. Content and organic, monthly. Reviewing an SEO campaign daily achieves nothing.

How long before judging a campaign? Long enough to accumulate data, not a fixed number of days. With three conversions you conclude nothing however many weeks pass.

Is it worth measuring return if my sale closes by phone? Yes, but you have to close the loop manually: ask every customer how they found you and write it down. It is tedious and it is the only way to know which channel pays.