A shopper sees your product in a Meta ad on Monday, forgets about it, then searches your brand name on Google Thursday and buys. Last-click reporting hands the entire sale to Google. Meta gets nothing, even though it's the reason the shopper knew to search for you in the first place. Pause Meta because it "isn't converting," and you've just cut the campaign that was quietly doing most of the work.
The honest answer is that a store needs a measurement stack that can see the whole path a shopper takes — not just the last thing they clicked before checking out. That means a product feed that tells the platforms what was actually bought, GA4 tracking that sees the same shopper across sessions, and each platform's own conversion tracking sending data back directly from your site instead of relying only on what a browser cookie can see. Built together, those three pieces show you which ads actually started a sale, not just which one happened to finish it.
Why last-click gets the story wrong
Last-click attribution — crediting the final ad someone touched before buying — is the default in a lot of reporting because it's the simplest thing to measure. It's also the version of events most likely to mislead you. A shopper rarely buys off the first ad they see. They see something on Instagram, look it up later, maybe click a retargeting ad the next day, then finally buy through a plain Google search for your brand name. Every platform in that sequence except the last one gets treated, in a last-click report, as if it did nothing.
That matters because budget decisions get made off these reports. If prospecting campaigns — the ones introducing your store to people who've never heard of you — never get credit for the sales they eventually lead to, they look expensive and unproductive next to a brand-search campaign that's just catching shoppers on their way to buy anyway. Cut the prospecting spend to fund more of the "better performing" brand campaign, and you've cut the top of your own funnel. The brand campaign runs out of new shoppers to catch within a few months, because nothing is introducing your store to anyone new anymore.
The three pieces that have to work together
A product feed is the file that tells Google Shopping, Meta, and other platforms exactly what you sell — the price, the image, the availability, the specific item — so an ad can show the actual product a shopper is looking for instead of a generic message. Without an accurate, regularly updated feed, shopping ads either show the wrong price or stop showing at all, and platforms can't connect a sale back to the specific product that drove it.
GA4 — Google's analytics platform — is what lets you see a shopper's path across more than one visit, instead of treating every session as if it came from a stranger. It's what makes it possible to notice that the person who bought after a Google search first landed on your site three days earlier from a Meta ad.
The third piece is each platform's own conversion tracking, sent directly from your website or store platform rather than relying only on a browser cookie. Browsers and privacy settings have made third-party cookie tracking increasingly unreliable, which is why tools like Meta's Conversions API and Google's server-side tagging exist: they send a confirmed sale back to the ad platform from your own server, so the count isn't left to whatever the browser happened to see. Skip this piece and you're not short on data by a little — you're short by however many sales the browser never reported at all.
Read it as assisted conversions, not just last-click
Once the tracking underneath is solid, the useful question changes. Instead of asking which campaign got the last click, ask which campaigns touched this shopper anywhere along the way. Most platforms and GA4 report this as assisted conversions: sales where a given campaign wasn't the last touch, but was part of the path. A prospecting campaign with a low last-click count and a high assist count is doing exactly its job, finding shoppers who go on to buy somewhere else in the funnel.
This is also where tracking and analytics infrastructure earns its keep for a store: the goal is a measurement setup that can tell prospecting from closing, so you can fund both instead of starving the one that doesn't show up in a last-click report. It's the same discipline behind auditing what a conversion tag is actually counting — a number that looks clean can still be measuring the wrong thing.
Where to start
If you're not sure your store is crediting the right ads:
- Check whether your product feed is current and connected to every platform running shopping ads, not just Google.
- Confirm GA4 is set up to track a shopper across sessions, not just within a single visit.
- Turn on server-side conversion tracking (Conversions API, server-side tagging) on top of the standard pixel, so browser privacy settings aren't quietly hiding real sales.
- Look at assisted conversions before you cut a campaign for looking weak on last-click alone — it may be the one starting the sales another campaign is finishing.
None of this requires ripping out what you already have. It usually means connecting three things that are already half-built — the feed, GA4, and each platform's own tracking — so they tell you the same story about the same shopper, instead of three different platforms each claiming the same sale. For an online store, that's the difference between reading your reports and actually knowing what's working.