Simplifying Google Ads Attribution Models

February 28, 2019
Posted in Paid Search
February 28, 2019 Jen Lopez

Simplifying Google Ads Attribution Models

If you’re an advertiser setting up PPC campaigns, or a business owner meticulously measuring the effectiveness of your PPC campaigns, you’ve likely heard the term “attribution” thrown around. Attribution is the process of identifying which ad clicks should receive credit for your conversions and how much credit. Attribution can get complicated the more channels you advertise on (i.e. Social, Display, etc.), however when looking at attribution in just the vacuum of your PPC campaigns, it’s actually pretty straightforward.

A fun way to think about attribution is all the different ways your professors could have graded group projects.

Let’s walk through a detailed analogy that works to simplify the different ways you can attribute website conversion in Google Ads. To start, there are six attribution types you’ll see when setting up your conversion tracking in the Google Ads interface. For our purposes – that means there are six ways your teacher can choose to grade your group project:

  • First Click
  • Last Click
  • Linear
  • Time Decay
  • Position-Based
  • Data-Driven

First Click Attribution – You know how every group project tends to have a leader? The person who steps up in the awkward first meeting and says, “This is how it’s going to go!” If a teacher graded your project based on first click attribution, they would give this rising star an A+, but everyone else would fail, no matter how much work they did. Kind of sad, huh?

While it doesn’t seem to make a ton of sense initially, this is a really valuable attribution model for many, because it will give all the credit to the first paid search keyword that introduced a customer to your brand or website (as measured through a click). The key though, is that the conversion has to take place within 30-days of a user clicking on an ad associated with that keyword for it to get the credit (unless, of course, you adjust your attribution window, which is more valuable for businesses with a long lead to close time). First Click attribution can often show surprising things – like how non-brand keywords may be the first ad to put someone into your sale cycle. In some other models, like the one below, more credit is often given to other keywords closer to conversion.

Last Click Attribution – We know who the leader was in our group projects, but what about the person who pulled through at the last minute? The one who you thought was slacking, but it turns out that although they procrastinated, they handed their work in at the 11th hour and it was actually good? If your professor was grading based on Last Click attribution, this guy would be the one to receive the A+, while the rest of the group failed miserably.

With Last Click attribution, Google attributes all the credit from a sale or lead to the keyword associated with the last PPC ad that was clicked prior to conversion. In many cases, we see those keywords being “branded” or very high intent, with modifiers like “buy XYZ”. This is also the default attribution model in Google Ads, so is likely being used by most advertisers. It often overvalues brand searches, or lower funnel keywords, so it’s important that you are pulling the conversion reports to truly understand the value of all keywords in your account beyond just how that conversion is attributed.

Linear Attribution – This is probably how we all did get graded on our group projects, as a group! No matter if you pulled all the weight for the slackers, your professor decided to give you all the same grade. The horror!

While often being credited as being the “fairest” attribution model for PPC, Linear attribution distributes credit from leads or sales equally among all clicks on the path to conversion. This means that each keyword that triggered a clicked ad along the conversion journey will receive equal credit. So, if you get a $20 sale, and ads were served and clicked on from two keywords before the purchase, Google Ads would show that each keyword was responsible for $10 in sales.

Time Decay Attribution – Have you ever approached a group project with the idea to do a “round-robin” rotation? For example, let’s pretend you have a research paper due and you have three people in your group.

Person #1 would be responsible for all the research for the paper and putting together an outline of the planned research paper. Person #2 would be responsible for following the outline and writing the paper. Person #3 would be the final pass-through. They would proofread, fact check and make sure the paper is printed and turned in on time.

Sound reasonably fair? Well, to your professor, no! With a Time Decay attribution model, he would be giving the highest grade to Person #3, since he played the most recent role in the project. Person #2 would get a lower grade, and Person #1 would receive the lowest grade. Dang.

The Time Decay attribution model gives more credit to clicks from keywords and ads that triggered closer in time to the conversion –it’s based on recency. Credit is distributed using a 7-day half-life. This means a click 8 days before a conversion gets half as much credit as a click one day before the conversion. This model relies on the concept that recency wins, and not every advertiser is buying into it.

Position-Based Attribution – Remember the leader in your group project? And the person who came through at the 11th hour? If a professor was grading based on position, he would give decent grades to the one who initiated the group project, and the one who finished it. The other contributors? They would get lower grades.

Similarly, with Position-Based attribution, Google Ads will give 40% of the credit to both the first and the last clicked ads and corresponding keywords that ultimately drove a conversion. Then, Google will split the remaining 20% of the credit among other clicks that happened in the middle of the path.  The model tends to value high-level level generic searches, as well as high-intent, lower-funnel brand searches, but all the research phrases typed in along the way, that ultimately helps a user convert, are less valuable in this model.

Data-Driven Attribution – Now let’s say you’re already familiar with the team you’re working on your group project with. In fact, you’ve done loads of projects together for this class already. If using a data-driven grading system, your professor will grade the team members based on how much each of you have contributed on past projects – in aggregate. Yes, some assumptions are being made, but in order for him to do this, you’d have to have worked on a significant amount of projects together – maybe one a week for the entire semester.

When we bring that concept into Google Ads, it does roughly the same thing. With this model, Google will distribute credit for the conversion action based on past data for the conversion action. What’s more, is that this feature is only available to advertisers with sufficient data, and it relies on Google’s algorithm which changes slightly with each new lead or sale. This type of attribution model is for the adventurous, who aren’t afraid to test their data, so, it goes without saying, but before employing this one, you want to have a sufficient amount of GOOD conversion data.

While the above analogy works to explain how attribution can be modeled for Google Ads within the platform itself, you’ll have to consider more factors if you are an advertiser or a business with a wider purview. If you are running more channels, or also tend to get organic and direct load traffic, you’ll want to make sure you also set up how you want to attribute credit among those channels in Google Analytics (or similar). Luckily, much of the terminology is the same!

Do you need help determining the best way to attribute credit to your paid search ads, or among other channels like paid social? Reach out to our team for more information.