A guide to attribution in Google Analytics

Where are our sales coming from?

We’d love to give you a simple answer, but the reality is that conversion attribution isn’t always a simple sum. We’ll try and explain why.

Client: “In August Google Analytics is reporting revenue from social as £5,521.71, whereas Shopify is reporting it at £3,357.75, which is right?”

Launch Account Manager: “Are you sitting comfortably, then I’ll begin…”

Firstly, it is really important to remember that you can’t track every sale. There are too many buying decisions which can’t be reflected in data – so all reporting is doing is giving you an indication of the sales which can be tracked, but not 100% of your sales.

The path to purchase is rarely ever one visit to your website = one sale. It’s likely that a user will visit the website several times, on several devices and may even have an offline interaction, get a recommendation, read a press article, and so on. 

As a result, website conversion reporting is not simple – especially when each platform uses different ways of tracking sales!


Last-Click attribution

Most reports track ‘Last Click’ and attribute the purchase to the channel that sent the user to your website before the purchase was made. The problem is this excludes the impact of all those other channels that contributed to that sale.

Let’s say a user searches “wooden toys to buy online”, clicks on Google Ads, comes to a website, and finds something they like. They want to see if it’s cheaper elsewhere. They go back to Google and search for the product name. Shopping results come up, they see you offer the best price, they click on your Shopping ad, arrivate at the website and then get distracted by a child swallowing marble in the lounge.

Later when they are in bed with a glass of wine, they scroll through Facebook, like a picture of their friend’s baby and then see your Facebook ad. They remember they haven’t bought Jonny’s sustainable wooden tractor, click on the ad, and buy it.


Michael Bergmann

Shopify and Facebook will credit Facebook for that sale (if the user wasn’t in private browsing mode in Safari… but that’s another story – Google ITP 2.0) and yet two Google campaigns contributed to this sale and were responsible for the user finding your brand in the first place – which will only show up in the Google Analytics (GA) multi channel funnels report.

Top Conversion Paths

The reports we give clients normally come from GA Top Conversion Paths, which attribute the sale to the channel whether or not it was the only channel used.

Top-conversion paths

This gives a better indication of the value of that channel. Obviously there are numerous sales which can’t be wholly tracked. That’s particularly true when mobile is involved, as users might not be signed in and therefore reporting is only an indication of the value from a particular campaign. This article explains it well. 

In addition to the above, each channel uses slightly different code/method to track a sale – Facebook tends to over report as it also credits a sale where there is an impression (“The default Facebook attribution window settings show actions taken within 1 day of viewing your ad and within 28 days of clicking your ad.”). Shopify will be last-click only and Google Analytics is last-click in some reports except the Multi channel funnel report.

On top of all of this, changes to iOS devices using Safari (ITP2.0) mean that tracking from mobiles has got harder, so we can’t track the campaigns as accurately as before.  GDPR has also had an impact with cookie prevention and ad blocking software.

Are you still there?


Hutomo Abrianto

We hope this helps shed light on why the figures don’t always tally. It’s a constant challenge for our industry and just as things were getting better, GDPR came along to complicate things. 

Word on the virtual street is that one day, tracking will be impossible because of user privacy – enjoy the flawed reports while they last, as soon we might not have any reporting!

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