What Is Performance Marketing? The Metrics, and Where They Stop Being True

Performance marketing is advertising where you pay for a defined action rather than for exposure. A click, an install, a lead, a sale. The action is agreed in advance, it is measured, and the invoice follows it.

That is the whole definition. What makes the category worth understanding is not the pricing model, which is simple, but the measurement underneath it, which is not. "Performance" means the action is counted. It does not mean the count is complete, or that the action was caused by the ad. Most of the money wasted in performance marketing is wasted in that gap.

This guide defines the metrics precisely, shows what the major platforms actually do today rather than what older guides describe, and is explicit about where the measurement stops being trustworthy.

What you are paying for

The further down that table you go, the more of the risk moves off your side of the table, and the more the publisher will charge to carry it. There is no free position. A CPA deal is not cheaper than a CPC deal, it is priced for the conversion rate the publisher expects.

The metrics, defined properly

Four numbers do most of the work. Define them exactly, because vague definitions are where reporting quietly drifts.

Click-through rate is clicks divided by impressions. It measures whether the ad earned attention from the people who saw it. It says nothing about whether those people were the right ones, which is why a rising CTR alongside a falling conversion rate usually means the creative is attracting the wrong audience.

Cost per click is spend divided by clicks. Useful for diagnosing auction pressure, useless as a success measure on its own. Cheap clicks from people who never buy are a cost, not a saving.

Cost per acquisition is spend divided by conversions. This is the number that decides whether a channel survives, and it is only meaningful next to what a customer is worth to you.

Return on ad spend is conversion value divided by ad spend. Google states it plainly as "the average conversion value (for example, revenue) you'd like to get for each dollar you spend on ads", and gives the arithmetic as "$5 USD in sales ÷ $1 USD in ad spend x 100% = 500% target ROAS".

If you plan to hand bidding to Google's Target ROAS, the documented data minimums matter, because below them the system has nothing to learn from. Google lists at least 15 conversions in the past 30 days for Search and Shopping, at least 50 in the past 35 days for Demand Gen, and at least 30 in the past 30 days for Video Action campaigns.

Two caveats from the same page are worth taking seriously. "Setting a target that's too high may limit the amount of traffic your ads may get", which is the most common way an ambitious ROAS target quietly throttles a campaign to nothing. And after any change, Google advises waiting "1-2 conversion cycles" before judging the result.

Source: Google Ads Help, About target ROAS bidding, read 11 October 2026.

Attribution: most guides are describing a system that no longer exists

This is the part of performance marketing that has changed most and been updated least in the explainers.

Google Ads used to offer six attribution models. It now offers two. Its documentation states: "The first click, linear, time decay, and position-based attribution models are no longer supported by Google." Conversion actions that used them "have been upgraded to use data-driven attribution."

What remains is data-driven attribution, which "distributes credit for the conversion based on your past data for this conversion action" and is "the default attribution model for most conversion actions", and last click, which "gives all credit for the conversion to the last-clicked ad and corresponding keyword" and is still supported.

The practical consequence is that if you are reading a performance marketing guide that walks you through choosing between time decay and position-based, that guide is out of date, and so is any reporting template built on it.

It also means the credit assignment in your account is now a model output rather than a rule you chose. That is usually more accurate and definitively less auditable. When a channel's reported conversions move, "the model reallocated credit" is a real possible cause alongside "performance changed".

Source: Google Ads Help, About attribution models, read 11 October 2026.

An impression is not a view

Display and video budgets are the easiest to waste, because the thing being counted is further from the thing you want than anywhere else in the stack.

The Media Rating Council sets the standard for when a served ad counts as viewable. For display, two conditions must both hold: "Greater than or equal to 50% of the pixels in the advertisement were on an in-focus browser tab on the viewable space of the browser page", and "The time the pixel requirement is met was greater than or equal to one continuous second, post ad render."

For video the pixel requirement is the same and the time requirement doubles: "it is required that 2 continuous seconds of the video advertisement is played". The guidelines add a detail worth knowing before anyone sells you on completion rates: "This required time is not necessarily the first 2 seconds of the video ad."

Half the pixels, for one second, on a tab that happens to be in focus. That is the bar an impression has to clear to be called viewable, and viewability measures the opportunity to be seen rather than evidence that anyone looked. Treat viewability as a floor below which spend is definitely wasted, not as proof that it was not.

Source: Media Rating Council, Viewable Ad Impression Measurement Guidelines v2.0, read 11 October 2026.

Affiliate and influencer work has legal requirements, not just commercial ones

Performance marketing through affiliates and creators is where the compliance obligations live, and they are more specific than most briefs allow for.

The FTC requires disclosure of any "material connection" with a brand, which it defines as "a personal, family, or employment relationship or a financial relationship, such as the brand paying you or giving you free or discounted products or services." Free product counts, including when the creator mentions it later and unprompted.

Placement is prescribed, not left to taste. The disclosure must be "placed with the endorsement message itself" and hard to miss. The FTC specifically warns against putting it only on a profile page, only at the end of a post, or behind a "click MORE" button. On visual platforms it should be superimposed over the image with enough time to read it. In video it must be in the video, not only the description. On a live stream it should be repeated, because viewers arrive partway through.

Language is prescribed too. "Advertisement", "ad", "sponsored", "#ad" and "#sponsored" are acceptable. "Sp", "spon", "collab" and a bare "thanks" are not. And platform disclosure tools are not sufficient on their own, though you may use them "in addition to your own, good disclosure."

This is not a formality. The disclosure is what separates an endorsement from a deceptive one, and the liability does not stay neatly with the creator.

Source: Federal Trade Commission, Disclosures 101 for Social Media Influencers, read 11 October 2026.

When performance marketing is the wrong instrument

Three situations where paying per action will not do what you want, and saying so early saves a quarter.

When nobody is searching for the category yet. Performance channels harvest existing demand efficiently. They are poor at creating it. If the search volume for the problem you solve is near zero, a performance budget will find the few people already looking and then spend the rest badly.

When the sales cycle outruns the measurement window. A six-month enterprise cycle will not attribute cleanly to a click in month one. The channel can still be working while the dashboard says it is not.

When the conversion is cheap to fake. Pay per lead and you will get leads. Pay per qualified lead, defined by something the publisher cannot manufacture, or expect to spend the saving on cleaning the list.

How to start without wasting the first month

What good reporting looks like

Report the action, its cost, and its value, in that order, and name the attribution model next to the number. A conversion count without a model is not a measurement, because the same week can produce two different totals under data-driven and last click.

Then keep one number honest above all others: what a customer is actually worth. Performance marketing optimizes toward whatever you tell it to value. Tell it to value cheap leads and it will deliver cheap leads indefinitely, which is the most expensive outcome available.

If you want help auditing an existing account, our paid media work starts with exactly that question rather than with the campaign structure.

Sources

All read on 11 October 2026. These are the primary documents, and they change, so check them rather than a summary of them.

• About target ROAS bidding, Google Ads Help
• About attribution models, Google Ads Help
• Viewable Ad Impression Measurement Guidelines v2.0, Media Rating Council
• Disclosures 101 for Social Media Influencers, Federal Trade Commission