Ad spend you can't trace: how to see what your marketing returns
Why Meta, Google and TikTok together report more revenue than your Shopify store made, how to check the size of the gap, and how to set up tracking so every order has a source.
Updated November 14, 2026 · 3 min read
If you add up the revenue Meta, Google and TikTok each report, the total is usually more than your store sold. Each platform counts an order when its own ad came before it, so one order is claimed more than once, while other orders are missing from every platform because the browser never reported them. The spend is real and the return is unclear. Three steps make it clear: check the size of the gap, send every order to the platforms from the server, and give every order one source.
Check the size of the gap
Take one month and write down four numbers:
- Total sales in Shopify.
- Revenue reported by each ad platform, added together.
- Total marketing spend: ads, creators, email and tools.
- Orders in Shopify, and purchases reported by each platform.
Then work out:
- MER = total sales ÷ total marketing spend. This is the return on all your marketing, and it cannot be double counted.
- The overlap = platform-reported revenue ÷ total sales. Above 1, the platforms are claiming the same orders.
A store that sold $100,000 on $25,000 of marketing has an MER of 4. If its platforms report $140,000 between them, $40,000 of that is orders counted more than once. More on the metric in what MER is.
Why orders go missing
A platform can only optimize on the purchases it hears about. Browser tags lose some of them:
- Ad blockers stop the tag from loading.
- Browser privacy rules shorten or remove the cookie that links the click to the order.
- Shoppers click on one device and buy on another.
Send purchases from the server
Server-side tracking sends the purchase from the order record, not from the shopper's browser, so a blocked tag doesn't lose it. Zalify Pixel records visits, carts and orders on your store and sends purchases server-side to Meta, Google Ads, TikTok and other ad platforms from Shopify's own order record.
Tag every link
Put UTM parameters on every ad, creator and email link, with the same naming everywhere:
| Parameter | Use |
|---|---|
utm_source | The platform: meta, google, tiktok |
utm_medium | The kind of traffic: paid_social, cpc, email |
utm_campaign | The campaign's name or ID |
utm_content | The ad or creative |
Untagged links are where "direct" revenue comes from. The creative-level attribution guide has the exact templates for each platform.
Give each order one source
With visits tagged and orders recorded, each order can be tied to the ad, creator post or email that brought it. Zalify Attribution does this for Shopify orders and reports ads and email on the same orders, so a sale is counted once.
Read the numbers together
- MER for the budget: is marketing as a whole paying off, and is there room to spend more?
- Attributed orders for the mix: which channel and which creative to move money toward.
- Platform ROAS inside one platform: which ad beats which.
If you would like the tracking set up and the accounts run for you, see our paid ads service.
A checklist to run today
- Work out last month's MER and the overlap.
- Compare Shopify orders with each platform's purchases.
- Turn on server-side purchase events.
- Add UTM parameters to every live ad and email.
- Review MER weekly, and attributed orders by channel.
Sources
- Marketing efficiency ratio, Shopify
Frequently asked questions
Why do my ad platforms report more sales than Shopify?
Each platform counts an order if its ad was seen or clicked before the purchase, and a shopper often meets several ads. The same order is then counted by two or three platforms, so the sum is higher than what the store sold.
What is MER?
Marketing efficiency ratio: the store's total revenue divided by its total marketing spend for the same period. It is one number for the whole store and no platform can count an order twice in it.
Is MER better than ROAS?
They answer different questions. ROAS is one platform's view of its own ads and is useful inside that platform. MER tells you whether marketing as a whole paid off. Decide the budget on MER and use ROAS to compare ads within a platform.
Why are some orders missing from the ad platforms?
Browser tags are blocked by ad blockers and limited by browser privacy rules, so some purchases never reach the platform. Sending purchases from the server, from the order record itself, closes most of that gap.
Do I still need UTM parameters?
Yes. UTM parameters on every ad link are what let you tie a visit, and then an order, to the campaign and ad that brought it, independently of what the platform reports.
Give every order a source
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