Attribution Models In Google Ads (What & How)

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What Are Attribution Models In Google Ads? 

A consumer’s path to purchase is often not a simple one. Before making their purchase, a customer will most likely do multiple searches in Google and interact with more than one of your ads. Attribution models in Google Ads allow you to choose how much credit each click gets for your conversions. The goal is to allow you to have a better understanding of the paths your customers take, and how your campaigns, ads and keywords perform. In turn, this helps you leverage performance across the user’s conversion path as well as reduce wasted spend.

Consumer Journey Example

The user journey tends to be very fragmented. Take the example below, following a user’s path to buying sport shoes. In this journey, the consumer has made 4 searches on 4 different days using different search terms. On the fourth search (Saturday), they have made their purchase after searching for “asics GT-1000 8 running shoes”.

SundayTuesday Friday Saturday
Consumer Searched Term“best sport shoes”“asics shoes”“asics running shoes”MADE PURCHASE“asics GT-1000 8 running shoes”

All searches played a role in getting the consumer to purchase, but which search gets the credit?

This is where attribution models come in handy allowing you to choose how much credit each ad and corresponding keyword gets for the conversions.

Different Types Of Attribution Models

Google Ads offers 6 different types of attribution models.

      1. Last Click Attribution

Last Click Attribution is the default attribution type in Google Ads. As the name suggests it gives all credit for the conversion to the last clicked ad and corresponding keyword.

In our example, the ad that showed when the user searched for “asics GT-1000 8 running shoes” will receive 100% of the credit for the conversion, disregarding all previous searches. It doesn’t give you the full story, just the end.

      2. First Click Attribution

The opposite of Last Click Attribution is First Click Attribution. It gives all the credit for the conversions to the first clicked ad and corresponding keyword.

This time round, the ad that showed when the user searched for “best running shoes” will receive 100% off the credit for the conversions, disregarding all searches that occur after. This attribution model also doesn’t give you the full story, just the start.

      3. Linear Attribution

Linear Attribution distributes the credit for the conversion to every interaction a user takes equally.

In our example, this means, each touchpoint gets an equal percentage of credit. As there are 4 touch points, each will receive 25%, adding up to a total of 100%. Compared with last and first click, linear attribution gives you a much fuller story.

      4. Time Decay Attribution

In the Time decay Attribution model, Google Ads gives the most credit to the touchpoint that happened closer to the final conversions. Specifically, credit is distributed using a “7-day half life”. According to Google, “a click 8 days before a conversion gets half as much credit as a click 1 day before a conversion.

Using our example, ‘asics GT-1000 8 running shoes” would receive the most credit as it was searched the closest to the conversion. “Best running shoes” would receive the least credit since it was the earliest.

       5. Position Based Attribution

The Position Based Attribution model gives 40% of the credit to both the first and last touch points. The remaining 20% is distributed equally among the other touch points.

In our example, both “best sport shoes” and “asics GT-1000 8 running shoes” receive 40% of the credit each, while the remaining 20% is given to “asics shoes” and “asics running shoes” (10% each).

        6. Data Driven Attribution

The newest Google Ads attribution is Data Driven Attribution. It works by using Google’s Machine Learning and past data in the account for this conversion action, giving credit to the ad and corresponding keyword with the most impact in the conversion process.

Data Driven attribution is only available for advertisers with over 15,000 clicks, 600 conversions within 30 days in Google Ads.

In our example, each touchpoint would receive part of the credit, depending on how much it influenced the user to converting.

The Advantages Of Using Attribution Models In Google Ads

      1. Understand your consumer’s conversion path

Understanding your consumer’s path to conversion gives you a better idea on where to invest your advertising spend. For example, after switching from Last Click Attribution to Linear Attribution, you may notice that your upper funnel campaigns, keywords and ads are receiving more credit than before – these are showing more value than you initially saw so you may want to invest more here.

The reverse is also true; it allows you to reduce wasted spend. You may find certain campaigns, ads or keywords that do not perform well towards your business goals.

        2. Using an Attribution Model that suits your business

With 6 models to choose from, there will certainly be a model that works best for how people search for what you offer.

For example, if you own an automotive sales company, a Linear Attribution model allows you to see the value of both upper funnel advertising (when people are doing more general research on cars) as well as campaigns, keywords and ads that generate leads or sales for your business e.g. “book a demo Toyota Corolla”.

         3. Optimise your bidding

Using the best model for your business and understanding your consumer’s path to conversions allows you to optimise your bids based on a better understanding of how your campaigns, ads and keywords perform.

How To Change Your Attribution Model In Google Ads

After deciding on the best attribution model for your business it’s time to select that model in Google Ads.

To do this, login to your Google Ads account and select “tools & settings” at the top right hand corner of your Google Ads interface.

Google Ads search tools & settings

From there you want to select “conversions” under the measurement heading.

measurement. and conversions

In the conversions page, select the conversion action you would like your chosen model to take affect on. In this example, we have chosen a purchase (transaction) conversion action.


Once you have clicked on your chosen conversion action, you’ll be greeted with a settings page. Click “edit settings” at the bottom of the page.

edit settings

From here, you can choose your desired attribution model by using the drop down tool. Once you have chosen, click “done”.

change the attribution model

Understanding Conversion Delay After Switching from Last Click Attribution 

After switching from the default Last Click Attribution in Google Ads, you may see a decrease in conversions the day after the change. Why?

Backfilling occurs. Non-last click models inherently shift credit for conversions backwards in time.

Consider our example again and say we have switched from last click attribution to linear attribution (credit is distributed equally across all touch points). When the consumer makes the purchase on Saturday by searching “asics GT-1000 8 running shoes”, it gets 25% of the credit. Friday will get 25%, Tuesday will get 25%, and Sunday will also get 25%. Therefore you may see a “dip” in conversions over the most recent days. However, It’s important to note that this is not a drop in conversions, but a reassignment of credit for recent conversions backward in time


Understanding Attribution models in Google Ads helps you better understand your consumer’s path to conversions. They give credit to different ads and corresponding keywords based on the model you use. This will allow you to make more informed decisions on where to invest your advertising spend as well as how to optimise your bidding.

If you have a specific question about Google Ads attribution or conversion delay please  contact us now.

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