3 Biggest Mobile Ad Tracking Pitfalls Explained & How to Deal With Them [Updated June ’19]

Missing 30% of Mobile Revenue

3 Biggest Mobile Ad Tracking Pitfalls Explained & How to Avoid them

Updated June ’19 – Thanks to Chris Shuptrine from Adzerk for helping me update this article! 

At its start, mobile advertising suffered from a major flaw: tracking performance was a nightmare. And how has that changed in the 10+ years we’ve had smartphones?

Well, not that much.

In fact, due to privacy regulations and moves by Apple and Google to limit cookie tracking, it’s arguably gotten more difficult.

In this post I’m going to outline the major handicaps you should watch out for when doing mobile ad attribution – and how to address them. This insight is based on my time as PayPal EMEA’s Display & Mobile Advertising Manager, where, as you can expect, we spent a lot on mobile ads. 

Don’t hesitate to add comments or questions… I am certainly not covering every aspect here and tried to keep things simple. A ‘thank you’ goes to the team at Conversant UK, who have been instrumental in getting these insights

Why should I even care?

Mobile advertising has already surpassed desktop ad spend and is predicted to reach 75% of digital spend by 2022. Much of this spending is in-app too, with 82% of all mobile spend being in-app, driven heavily by social networks like Facebook, Twitter, Snapchat, and Instagram.

And what are the mobile tracking issues you speak of?

First, let’s do a quick, high-level look at digital tracking tech and some of their respective pitfalls.

Web advertising (Desktop & Mobile)

These are ads that appear on desktop or mobile browsers, which then send clickers to your site. To make it easy to track performance and rotate creatives, most companies doing web advertising will be serving these ads via an ad server such as Google Ads Manager.

Historically, the way browser advertising works is that when an ad is shown, a cookie is dropped by the third-party ad server onto the user’s browser (even if they don’t click). This cookie could live in the browser for years, depending on the browser and the settings of the ad server (and if the user hasn’t reset their cookies). The ad server will also assign a cookie click ID to that user if they click.

Then, if a user performs a desired action using the same browser (like ordering your beautiful sunglasses), the cookie fires again, and the ad server reports a tracked sale attributed to that campaign. Happy days!

This is a simplified example, but it’s pretty much how web advertising worked for decades. As I’ll touch upon shortly, though, in the past year we’ve seen industry-wide changes that have severely hampered this process.

Tracking on Desktop & Mobile Web to Web on Chrome, Firefox & IE
Tracking on Desktop & Mobile Web to Web on Chrome, Firefox & IE

Well, the good news is that this works on Chrome, Firefox, IE & Opera (> 95% of the desktop market). However, Apple decided to make things slightly more complicated (otherwise, what would people like me be hired for?). On Safari, 3rd party cookies are blocked by default. This leaves us in a slightly messy situation with 2 scenarios:

  • 1 User does click on your ad: Cookie will be dropped, happy days😎.
  • 2 User does not click on your ad: Cookie will not be dropped, unless:

i) the user has visited the ad server’s domain before e.g. by clicking on another ad using the same ad server OR

ii) the cookie is from the same domain as the one that’s requested (typically a First-Party-Cookie)

Tracking Web & Mobile Web to Web on Safari
Tracking Web & Mobile Web to Web on Safari

On mobile, this presents a challenge to advertisers as Safari’s market share is around 36% globally. It basically means that no-view through-tracking is possible for a large share of that traffic. A conservative estimation is 50% of that, leaving us with 18% of mobile traffic untracked for post-view conversions.

See how things are getting a little messy?

In-App Advertising (Mobile App to Website)

Here, your ads are appearing within a mobile app, such as Facebook or Words With Friends, and are linking out to your website.

Where this differs from the mobile browser scenario is that in-app ads don’t send users outside the app.  Instead, as you’ve probably noticed, it opens an in-app browser, so that when exit out of the browser, you are still in the app.

The shortfalls of this are: (1) a cookie doesn’t get dropped at time of impression, and (2) if they do click, a cookie is dropped, but only for that in-app browser session.

Tracking in-app to mobile-web
Tracking in-app to mobile-web

This means that view-through attribution (tracking whether a user buys after seeing the ad) is impossible, since a cookie is never dropped. Additionally, if the user doesn’t convert straight away (during that session), the ad server will never be able to tie a future purchase to that click/campaign. This could lead to underreporting, so that the campaign looks worse than it actually performed.

There is a workaround for some ad platforms, such as Facebook, though. It involves installing their conversion pixel on your website. Facebook, for instance, is able to track the # of purchases that happen within 1 day of view or up to 28 days of click. The downside of this is that (1) the data is not independently verified by a 3rd-party ad server, (2) it’s just a basic count of purchases, and (3) you have no user-level information to work with.

In-App Advertising (App to App Store)

Here, you are showing ads within an app and directing clickers to your app’s listing in the Google Play Store or Apple App Store.

It’s important to understand that app download attribution does not use cookies. App to app tracking instead uses mobile identifiers, including:

  1. Your mobile device’s unique ID. In Android, this is known as the Google Advertising ID (Google AID or AAID); iOS uses the Identifier for Advertising (IDFA or IFA); and on Microsoft it’s the Windows Advertising ID (Windows AID)
  2. Device Fingerprinting – a method of approximating who the user is based on device information and other info, such as browser, time, etc

Without cookies, there’s no point in using a 3rd-party ad server for this type of advertising. Instead, for app-to-app marketing you’ll have to use a mobile app attribution solution such as Tune, Appsflyer, and Adjust. These are generally SDKs that you install in your app, which send Mobile IDs of anyone who first opens the app out to ad partners via server-side integrations.

The ad partners and the tracking solutions compare the IDs of clicks and downloads, and if there’s a match (i.e., the ad partner knows ID 12345 clicked on an ad, and the tracking solution knows that ID 12345 downloaded the app shortly thereafter), then the attribution platform assigns a download to that campaign.

Tracking app to (in-)app activity
Tracking app to (in-)app activity

As you can see, mobile ad tracking is complicated. To make it worse, there are some macro industry trends that are further impacting the reliability of mobile ad tracking:

  1. Ad blockers – These tools identify ad tech codes and block ads from appearing (usually leaving blank spaces where the ads would be). It’s expected that in the US by 2020, 27% of internet users will be using an ad blocker. The potential impact of ad blockers for mobile advertisers is that you’ll be charged for impressions that never actually get shown, making it difficult to get an accurate understanding of your campaign metrics.
  2. Apple’s Intelligent Tracking Prevention (ITP), which blocks third-party ad server ad cookies within the Safari browser. This is less of an issue for desktop users (as Safari accounts for just 5% of browser sessions), but on mobile phones it’s 25%+ and on tablets it’s 50%+, so ITP has some major mobile repercussions.

As background, in 2017 Apple updated Safari with Intelligent Tracking Prevention, a feature that blocks 3rd-party cookies. This means ad servers can no longer read what cookies are on the user’s browser (a practice that allows for retargeting and user-level targeting), nor can they do view-through ad attribution, since no cookie is dropped.

Apple did allow the dropping of 1st-party cookies (aka, a site could drop a cookie if the user visited their domain). This cookie would persist for 30-days and would be readable only by the same site. Due to ad tech companies gaming this system, though, their 2019 ITP 2.2 update now restricts this to seven days. No cookie, therefore, ever persists on a user’s Safari browser more than a week (unless the person revisits the website).

ITP’s impact on the mobile ecosystem are:

  1. No view-through-tracking is possible for a large share of mobile traffic. So, when you’re looking at campaign performance, your campaigns could be delivering better results than you think
  2. Even if you manage to drop a first-party cookie, if someone makes a purchase more than seven days after clicking, you won’t see it. Depending on what your average purchase window is, this could greatly impact how the campaign looks to be performing

All of this is caveated, however, by even more potential upcoming changes to Safari: the Ad Click Attribution API, which is currently not released. The idea behind this is that first-party advertisers will get conversion counts for campaigns beyond 7-days, though they can’t tie a conversion to a particular user.

This could allow for conversion count tracking, but has major limitations, including the inability to use a third-party ad server and zero insight into which purchase the user made.

  1. Upcoming cookie changes to Chrome. As Chrome accounts for 60%+ of the total browser market, any updates to their cookie tracking policy could have a dramatic impact. While nothing has changed yet, they’ve insinuated that they’ll likely be blocking third-party cookies in the future, just like Apple did.
  2. The Global Data Protection Regulation (aka GDPR). This EU law is the most sweeping privacy law ever enacted and forces sites/apps to ask for consent from users to use their data in ad tracking and attribution. For advertisers, this means that your ad server / ad partners may limit the information you can access on users who see or click on an ad, thereby reducing the data you have to make informed decisions.
  3. The removal of the DoubleClick ID. In response to the GDPR, in May 2018 Google (the largest ad server in the world) announced it would no longer let advertisers export the DoubleClick ID, a practice most companies did for cross platform reporting and measurement. This further limited an advertiser’s visibility into campaign performance.

So how do you address these mobile tracking limitations? There’s not going to be a magic bullet here, but some steps to alleviate their impact are below.

  1. Not spend on Safari – If attribution accuracy is your concern, you can blacklist Safari from your ad campaigns (most platforms allow for browser targeting). Please note, though, that the Safari limitations will lead only to underreporting. So, if it’s working for you, no reason to stop.
  2. Employ simple mobile web flows for in-app campaigns – For instance, if you know that Facebook is directing clickers to an in-app browser with a short-lived cookie, you could ask for just an email address and then follow up with them later. Alternatively, you could create some urgency (e.g. limited time offer) to push them to make an action in that session.
  3. Use both an ad server and an in-app tracking partner. There’s currently no solution that does both, so you’ll have to be okay working with two attribution partners.
  4. Use mobile ad platforms that have their own tracking capabilities. For example, installing the Facebook and Twitter tracking pixels and spending heavily on those two sources.
  5. Anticipate revenue leakage and build it into your models. At PayPal, we estimated that tracking limitations led to underreporting of about 15% of total marketing-driven mobile revenue. It’s probably closer to 20%-25% now. So, when looking at the value of your campaigns, you could artificially inflate results by 20% to get closer to the real number.

Thanks for reading! I would love to hear your own experiences in the comments. And don’t forget to sign up to my newsletter below to get new articles on growth & digital marketing straight to your inbox.


Thanks! Johannes😊

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Hi, I am Johannes! 🚀Digital Nomad, Former Head of Growth @Truly (trulyexperiences.com), Former PayPal Global SEO lead & Paid Media marketer, 500 Startups mentor & growth consultant. In my spare time, I love 🚴‍♂️, ✈️🌏🗺,🎾. Get in touch: via Email or Tweet @joradig.

7 thoughts on “3 Biggest Mobile Ad Tracking Pitfalls Explained & How to Deal With Them [Updated June ’19]”

  1. Great introduction to the world of Mobile attribution. I’ve been doing lots of analytics work recently and it can be hard enough connecting SSL, social, sub-domains and SaaS cart solutions before you even think about mobile! Google Tag Manager has made a big difference to the work flow, although haven’t had a chance to use it in-app just yet and still doesn’t nail the lost sessions without extra measures.

    1. Hi Daniel, thanks for your comment! I definitely agree, Google Tag Manager makes tracking a lot easier, but in the mobile space it’s not exactly on par. Well, there’s always going to be interesting work to be done 🙂


  2. Hello. You talk about the issue being with cookies and post view attribution. I also have a problem with Google UTM tags being stripped so my GA is under reporting. My head of analytics says I’m wrong as this can’t happen. I’m convinced I’m right. I’m missing up to 30% Facebook traffic in GA, which is largely mobile and largely from IOS devices. He says my Facebook reports must be wrong? Is he in denial that GA is just not good enough to measure paid campaigns on mobile or any device?

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