Ads Manager says the campaign delivered 120 purchases this week. Your store says only 85 orders came from Facebook. Or the other way round. Which one is right? Usually both are — they're measuring different things. Understanding why saves you bad decisions and awkward client conversations.
What is attribution?
Attribution is the rule Meta uses to decide when to credit a purchase to an ad. Someone may see your ad today and buy three days later. Was that purchase driven by the ad? It depends on the attribution window: how long is allowed between interacting with the ad and buying.
Types of Facebook ads attribution windows
| Window | What it means |
|---|---|
| Click-through | The person clicked the ad, then bought within a set number of days (e.g. 1 or 7) |
| View-through | The person saw the ad without clicking, then bought within a short period (e.g. 1 day) |
| Engaged-view | For video ads: watched part of the video without clicking, then bought within a short period |
A common setting is 7-day click and 1-day view, but it can be changed at the ad set level, and Ads Manager shows it in the Attribution setting column.
Why the numbers differ: 6 reasons
- View-through purchases: Ads Manager counts people who saw the ad and bought within a day, even if they came to the store via Google search. Your store will credit Google.
- Reporting date: in default reports, results are usually attributed to the day of the ad interaction, not the purchase day. A Tuesday purchase can show up under Sunday.
- Multiple devices: seen on a phone, bought on a laptop. Meta may connect the two; your store usually can't.
- Lost events: privacy limits and ad blockers mean the pixel misses some purchases, so Meta sometimes relies on statistical modeling.
- Cancelled and returned orders: Ads Manager records the purchase when it happens and never learns it was cancelled.
- Time zones: if the ad account and store use different time zones, some orders shift between days.
How privacy restrictions affect the numbers
Since phones and browsers began limiting cross-app and cross-site tracking, Meta no longer sees every purchase directly. To compensate, it partly relies on statistical modeling to estimate some results. That means part of the numbers in Ads Manager are estimates, and figures can shift slightly in the days after a period ends as delayed data arrives. So don't judge yesterday's final performance first thing this morning — give the numbers a day or two to settle.
Example: the same campaign under different windows
| Attribution window | Purchases | ROAS |
|---|---|---|
| 7-day click and 1-day view | 120 | 4.2 |
| 7-day click only | 98 | 3.4 |
| 1-day click | 80 | 2.8 |
(Illustrative numbers.) Same campaign, same sales — three different readings. There's no universally "right" window; what matters is knowing which one you're reading and always comparing like with like. In Ads Manager you can compare windows side by side with the "Compare attribution settings" option under Columns.
When to change your attribution window
- If your buying cycle is long (an expensive product that needs thought), a longer click window reflects reality better.
- If the product is cheap and the decision quick, a shorter window may be enough.
- If you change it, note the date, and don't compare numbers from before and after directly.
Whatever you choose, document it in your client reports so everyone reading the numbers understands what they include.
Which number should you trust?
Use each number for what it's good at:
- Ads Manager numbers: for comparing campaigns and ads with each other, since they're measured the same way inside the platform.
- Your store's actual numbers: for judging overall ad profitability and real return.
- Total revenue ÷ total spend (MER): a simple metric that doesn't depend on attribution, showing whether ads lift overall sales. We covered it in How to Calculate ROAS and Break-Even ROAS: When Is a Facebook Campaign Really Profitable?.
Most importantly, always compare like with like: don't compare this month's 7-day-click ROAS with last month's 1-day-click ROAS.
How to explain the gap to a client
"Ads Manager counts everyone who interacted with the ad and bought within a few days, even if they later bought through another route. The store counts only the last source a customer came from. So we use ad numbers to compare campaigns, and store numbers to judge real profit."
An explanation this simple stops clients doubting every number whenever they see a gap, and keeps results discussions calm.
Practical tips
- Add the Attribution setting column in Ads Manager so you always know which window you're reading.
- Don't change attribution windows often — each change makes comparisons with past periods unfair.
- Track the gap between Ads Manager and your store monthly. A stable gap is normal; a sudden jump signals a tracking problem: Meta Pixel and Conversions API: How to Make Sure Your Sales Are Tracked Correctly.
In Raqeeb Ads' Campaign Analyzer, results, revenue and ROAS are shown as Meta records them, and each period is compared with the previous one measured the same way, so comparisons stay fair.
A free tool that helps here: The UTM builder writes the tracking link, or the dynamic parameters you add to your ads once.
FAQ
What is Facebook's default attribution window?
Are Ads Manager numbers inflated?
Why does a purchase appear on a different day?
A media buyer running Meta campaigns for clients across Egypt and the Gulf, who built Raqeeb Ads to fix the account-monitoring problems he kept running into himself.