The difference between tracking conversions in Google Ads vs tracking via Google Analytics.

Short answer: Google Ads and GA use different attribution models and timings. Read further to learn more about attribution models and timings.

According to Google: An attribution model is a rule or set of rules, that determines how credit for sales and conversions is assigned to touchpoints in conversion paths.

In human words, an attribution model is a model that assigns credit to the steps your user takes to complete an action on your site such as a transaction, a newsletter subscription, or even a video view.

Steps can include actions such as: clicking on an ad, seeing an ad, following you on social, clicking on an add to cart button, … The options are endless. It brings you an answer to the million-dollar question “which clicks were responsible for the conversion?”. Knowing the answer to this question will not only help you to better examine your profits and losses of your campaigns but can also help you in better smart bidding activities in the future.

Attribution Model
GA uses the last non-direct attribution model for non-multi channel funnel reports and the last click model for multi-channel funnel reports. By default, it is set to the “Last Non-Direct Click” attribution model. This means that Google Analytics will credit the last channel a user is coming from before completing a conversion.

Google Ads is default set to a ‘Last Google Ads Click’ attribution model in which the last Google Ads click in a conversion path get all the credit for the conversion.

An example:

  • Day 1: A user clicks on your ad but leaves your page without converting
  • Day 6: The same user browses your company on Google and enters your page by clicking on an organic search result and decides to follow you on Facebook.
  • Day 10: Third time’s a charm: after seeing a Facebook post this same user decides to purchase something from your site.

Google Analytics attribution logic: Google Analytics credits social media for the conversion since this was your touchpoint

Google Ads attribution logic: Google Ads credits your ad for the conversion

Attribution Timing
Google Analytics describes attribution time as the time of the goal completion or conversion.

Google Ads defines attribution time as a time of the ad query the user interacted with.

For example, a user comes to your site on 11th Jan via an ad but leaves immediately without a further transaction. The same user comes back 5 days later on 16th Jan via a social post and completes a transaction.

Google Analytics will consider the attribution time as 16th January (the time of goal completion or conversion)

Google Ads will consider the attribution time as 11th January (the time the user interacted with the ad)

Google Ads just uses the last AdWords click’ attribution model in which the last Google click in a conversion path gets all the credit for the conversion

+---------------+------------------+------------+
| | Google Analytics | Google Ads |
+---------------+------------------+------------+
| January 2021 | €10 | €8 |
| February 2021 | €10 | €9 |
+---------------+------------------+------------+

At the end of January 2021, the Return On Ad Spend shows €10 in Google Analytics and €8 in Google Ads. Mid-February we check again and see that our ROAS in Google Ads has risen to €9 but in Google Analytics it remained €10... How does this come?

Simple, someone clicked on an ad of you in January 2021 but didn’t proceed with a purchase. Instead, this user returned in February and contributed to a purchase (conversion). Google Ads devotes this purchase to January 2021, but Google Analytics dedicates it to February 2021.

Important to note here is that the default cookie duration of a Google Ads cookie is 30 days, meaning if a user clicks on one of your Ads and lands on your page, a cookie will be put for 30 days.

Trying to figure things out while writing about it. Lover of design, front-end development and anything data-related