You will be able to explain why each platform reports a different number of conversions for the same campaign.
At the end of November, Farah put three numbers side by side. Meta Ads Manager said her ads had produced 34 purchases. Google Ads said 41. Her shop platform said she had 58 orders in total that month, from every source, including people who walked up to her stall at a bazaar and ordered on their phones. If both ad platforms were right, ads alone had produced 75 sales in a month that only had 58.
They were not lying, exactly. Each platform was counting by its own rules, and each was counting some of the same customers. This lesson explains why the numbers never agree, and how to use each one without fooling yourself.
An ad platform's job, from its own point of view, is to show what its ads achieved. So it counts a conversion whenever it can link a purchase or lead to someone who interacted with one of its ads, within a time window it sets. Paid ads: Meta, Google and TikTok covered how the pixel or tag reports actions back to the platform in its lesson 3.1, What a pixel does and why the auction needs it.
Each platform has its own rules. The attribution window is how long after an ad interaction a conversion still counts. Meta, Google Ads and TikTok each set their own defaults, which can differ by campaign type, and each lets advertisers change them. A purchase eleven days after a click may count on one platform and not on another. Check the current defaults in each platform's help centre and in your own campaign settings, because they change.
Platforms also differ on when a conversion is reported. Some assign it to the date of the ad click, others to the date of the purchase, so the same sale can land in different months in different tools.
GA4, meanwhile, uses its own attribution model from lesson 5.1 and sees only what happens on your website. It has no special loyalty to any ad platform.
Some platforms also count view-through conversions: someone saw an ad, did not click it, and later bought. Meta, for example, can count a purchase from a person who scrolled past an ad on Instagram and later typed the shop's address into a browser. The platform knows the person saw the ad because they were logged in to its app.
GA4 cannot see that. To GA4, the same customer arrived directly or through a search, with no ad involved. So the ad platform claims the sale, and GA4 gives it to direct or organic search. Neither is lying. They are looking at the same customer with different information.
Platforms also use modelling to estimate conversions they cannot observe directly, for example when people decline tracking on their phones. Those modelled conversions appear in the platform's totals with no individual record behind them.
Now go back to Farah's customer in lesson 5.1, who clicked a Meta ad, later searched on Google, and bought from the newsletter. If she had also clicked a Google search ad along the way, Meta would count the purchase, Google Ads would count the same purchase, and GA4 might give it to email. One sale, three claims.
Multiply that across a month and the totals drift well past reality. That is why adding up conversions from every platform almost always gives you more sales than you actually made. It is also why a business that runs on several channels can feel like every channel is profitable while the bank account says otherwise.
The fix is to decide which system counts the real total, and to stop asking the ad platforms for it. The source of truth is the system that records each actual sale or lead once, with a name or order number behind it: your shop platform, your booking system, your CRM or, for some businesses, an accounting system.
For Farah, it is the shop platform: 58 orders. For Priya's maths centre in Tampines, it is her enrolment spreadsheet. GA4 sits in between, a good guide to where website visitors came from, but itself an estimate, for the reasons in lesson 4.2.
Then give every other number a specific job. Meta's purchase count is for comparing Meta campaigns, ad sets and ads with each other, because all of them are counted by the same rules. Google Ads conversions are for comparing Google campaigns and keywords with each other, and for feeding Google's bidding. GA4 is for comparing channels on one consistent basis and for understanding behaviour on the site.
What you stop doing is comparing Meta's numbers with Google's directly, or adding them together, or reporting the platforms' totals to the owner as sales.
Once a month, put the numbers side by side, as Farah did: each platform's claimed conversions, GA4's key events and the real total from the source of truth. Do not try to make them match. Watch how the gap moves. If Meta claimed about 60 percent of real sales for months and suddenly claims 90 percent with no change in real sales, something has changed in its counting or your tracking, and that is worth investigating before you move budget.
Building that table for your own business is also the first piece of the attribution note you will write in lesson 5.4.
For one month, write down the conversions each platform claims and compare the total with real sales from your shop, booking system or CRM.
Junxiong-WFG Organisation is an authorised representative of AIA Financial Advisers Private Limited (Reg. No. 201715016G).