Measurement
Attribution, explained
Attribution is the set of rules that decides which ad gets the credit. Change the rules and the same campaign looks better or worse without anything real changing.
Someone sees your ad on Monday, clicks a different one on Wednesday, searches your name on Friday and buys. Which ad earned the sale? Attribution is how each platform answers that question, and each one answers it in its own favour.
Two ideas to hold on to
- The window. How long after an ad interaction a conversion can still be credited to it.
- The interaction. What counts: a click through to your site, some other engagement, or simply being shown the ad.
How Meta does it
You choose an attribution setting on each ad set. As of 2026 there are three kinds of interaction:
| Type | What counts | Windows |
|---|---|---|
| Click-through | A click on the ad's link | 1 day or 7 days |
| Engage-through | Other engagement, such as a like, share, save or a video watched for several seconds | 1 day |
| View-through | The ad was shown, with no interaction | 1 day, or off |
The usual default for website conversions is 7-day click, 1-day engage-through and 1-day view. Two changes are worth knowing if you are comparing against older reports. In early 2026 the longer view windows, 7-day and 28-day view, were removed from reporting. And click-through now means link clicks only, with other interactions moved into engage-through, which replaced the older engaged-view setting. A 28-day click figure is still available for comparison, though not as something to optimise toward.
View-through is the one to be careful with. It credits your ad whenever someone was shown it and then converted within a day, including people who were going to convert anyway. Use the Compare attribution settings option in Ads Manager to see how much of your result depends on it.
How Google Ads does it
Google Ads now offers two models for a conversion action. Data-driven attribution, the default, shares credit across the ad interactions on the path using Google's modelling of your account. Last click gives all the credit to the final ad clicked. The older first click, linear, time decay and position-based models were retired, so advice built around them is out of date.
Why the numbers never match
- Everyone claims the same sale. Meta and Google can each credit themselves for one purchase. Add the platforms together and you get more conversions than you had.
- Different windows and rules. A 7-day click window and a last-click model are measuring different things.
- Tracking gaps. Browsers, ad blockers and consent choices hide some conversions from one tool and not another.
- Different dates. Some reports date a conversion to the day of the ad click, others to the day it happened.
How to decide anyway
- Pick a setting and keep it. A consistent yardstick beats a perfect one. Changing settings mid-campaign breaks your comparisons.
- Use platform numbers to compare ads, not to count money. They are good at telling you ad A beats ad B. They are poor at telling you what you earned.
- Reconcile to a source of truth. Your CRM, your donation platform, your bank. Total real revenue divided by total ad spend is a number no platform can flatter.
- Test incrementality when the budget justifies it. Switch ads off in one region, or run a holdout test, and see what actually changes.
For charities. Match donations in your giving platform back to campaigns, and judge appeals on money that reached you after fees. That is a different number from the one Ads Manager shows.
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