Intelligent Tracking Prevention and conversion attribution

How 20% of your marketing budget goes up in smoke

Posted 28 April 2020 by Jacob Noordmans
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ITP can seriously disrupt insights regarding the use of marketing budgets. As a result, you may spend a large part of your money incorrectly. A simple one-off procedure using Cookie Guard can provide the solution.

Intelligent tracking prevention (ITP) is a technique designed to protect the privacy of users of Apple's browser Safari. It was introduced in 2017 and has evolved since then, as a result of a cat-and-mouse game between Apple and major adtech companies (making their money from online advertising and the technology behind it). ITP focuses on limiting cross-site tracking1. This is something that companies like Google, Facebook, and other advertising companies do on a large scale. ITP is trying to restrict the invasion of privacy caused by these large companies, which are everywhere on the internet. However, the way Safari does this has major (unintended) side effects.

The side effects of ITP

The way Safari (with ITP) fights cross-site tracking is, among other things, by limiting the capabilities of cookies and other forms of storage in the browser. This not only protects the privacy of the users. It also limits the effectiveness of tools that depend on being able to identify the user. Important applications that are affected are:

  • Conversion attribution
  • Marketing and remarketing
  • Personalization
  • AB-testing
  • Collecting website statistics
In this article we focus on ITP's impact on conversion attribution. By this, we mean the capability to link the costs of your online marketing efforts to their revenue. For example, you may run a campaign using Google Ads. Users will see your ads with their search results in Google. Because you can link the clicks on those ads to the transactions that take place on your website, you can determine which ad campaigns are successful and which are not. This way you can adjust what you spend on which campaign and use your marketing budget as effectively as possible.

Conversion attribution ensures that you can use your marketing budget effectively

Safari sees this as an invasion of user privacy. And, with ITP, has made conversion attribution very difficult. This makes it problematic for marketers to effectively manage their campaigns.

How ITP blocks conversion attribution

To understand what happens exactly, the following three components of ITP are important:

  1. There is an on-device list of common tracking domains. This list is based on the user's online traffic and activity.
  2. The lifespan of cookies and other forms of storage in the browser is limited depending on a number of rules.
  3. Restrictions are imposed on cross-site requests to domains listed at 1.
In this article we mainly look at points 1 and 2. Although points 1 and 3 together also yield an interesting story. Since the combination of these two can actually cause an extra privacy leak2. More about this in a future article.

In the present context, the main point is that the lifetime of all cookies that are set using JavaScript is limited. These JavaScript cookies (and other forms of storage in the browser) have a maximum lifespan of seven days. There are no exceptions to this rule. What many people don't realize is that pretty much the entire toolbox of the modern online marketer, CRO specialist, and online-data scientist is affected by this. It means that all tools that operate client-side (i.e. in the browser) only have limited storage capabilities. A major problem for personalization, AB testing, machine learning, etc.

The entire toolbox of the modern online marketer [...] is affected

However, there is a special case where Apple even takes it one step further. This brings us to conversion attribution. The special case happens when someone lands on your website, while coming from a domain that has been identified as a “tracking domain”. If he or she ends up on a page where the url contains query parameters or fragment identifiers, the lifetime of JavaScript cookies is limited to 24 hours. If you think this is rare and not a problem for you, please keep reading.

This “special case” is very common in the context of online marketing. A simple example of this is a Google Ads ad. A user searches for your product on and sees an advertisement. When the user clicks on it, he or she will land on a page where the product is sold. The URL in the browser will often look like this:

https://domain.example/coolstufftobuy?utm_campaign=mycampaign&utm_medium=cpc .

Pay particular attention to the parameters at the end of the url, the so-called query parameters. This is the part behind the question mark. These parameters indicate, for example, which advertising campaign led the user to the website (“mycampaign” in this case). Upon loading the page, this information is placed in a cookie by a piece of JavaScript. This allows future sales to be linked to the campaign, making it possible to analyse the costs and benefits of the various campaigns.

The online marketer is deprived of his senses

The problem is that the lifetime of the cookie containing the campaign information is only one day, because has been identified by ITP as a "tracking domain" and because the page's URL contains query parameters. Therefore, if the user makes his purchase the next day, it will not be seen as a result of this campaign. This deprives the marketer of her senses. She can no longer rely on the data to make decisions about campaigns.

This is your problem too

The key question is of course: does this also affect my webshop and my campaigns? And how big is the impact? And do I perhaps make marketing decisions based on data that is incorrect or incomplete? The exact answers to these questions are likely to differ between websites. But in general you can assume that ITP does have an impact. There is good reason that ads in Safari have decreased in value since 2017. The CEO of adtech company "Rubicon Project" says: 3

The allure of a Safari user in an auction has plummeted [...] There’s no easy ability to ID a user.

To be able to estimate the impact ITP has, you can look at the percentage of traffic or transactions on your website that comes from Safari. Suppose it is 40%. And suppose that in your industry on average 50% of users wait for a day before making their purhase. This means that potentially 20% of your marketing budget is misattributed. For most webshops this implies gross errors in their attribution overviews, leading to misguided and expensive decisions.

How Cookie Guard solves the problem

By now, every online marketer should ask himself: how do I solve this? How do I prevent 20% of my budget from being misattributed and thus appearing to go up in smoke? The solution lies in the way ITP assesses cookies.

How do I keep 20% of my marketing budget from going up in smoke?

As we mentioned, ITP affects cookies that are set using JavaScript, i.e. cookies that are placed by a command from the browser. However, there are also cookies that are placed on behalf of the server from which the website is served. These cookies are often essential to the website. An important difference with JavaScript cookies is that server-side cookies can only be placed with the permission of the website owner. After all, the owner manages the server where the website is located. These so-called HTTP cookies are not influenced by ITP. This is the solution that the Harvest Cookie Guard uses.

With the Harvest Cookie Guard you can transform your cookies into HTTP cookies, which guarantees their lifespan. A simple and one-off solution, but one that has major consequences for your complete client-side toolbox. In particular for the attribution of your marketing budgets. It contributes to the foundation of all your online activities: reliable data collection. This prevents many uncertainties and errors that can potentially be very expensive.

Would you like to try Cookie Guard one month for free? Contact us.

Or do our test to see if ITP impacts your analytics data.

The blocking of conversion attribution by ITP in action (in Dutch):

1 Cross-site tracking means that information about your visit to one website ends up with another website. By applying this at large scale, some big companies can piece together information about your behavior on large parts of the internet.