Advertising on mobile is big business. Recent Gartner research revealed that global mobile ad expenditure is forecast to be $11.4 billion in 2013, up from $9.8 billion in 2012.
A significant part of that business involves being able to monitor the success of mobile ad campaigns at the level of the individual user in order to be more accurate in providing ad content more likely to trigger a conversion or sale. A key consideration for app marketers is ad tracking and attribution, which is required to reveal what's working and where to focus marketing spend.
But there are challenges associated with choosing a mobile ad tracking solution. Mobile app conversion tracking presents unique challenges not found in traditional desktop browser advertising. There is no industry standard for mobile ad tracking so marketers are on their own to make sense of the different technologies and determine the best approach for their businesses.
Several tracking solutions are on the market today, each employing very different approaches. Some marketing channels and networks only support specific tracking solutions, so you need to understand the range of tracking solutions that's right for your marketing plans. Further complicating matters are the ongoing changes and privacy concerns, making it difficult for marketers to choose a tracking technology with confidence.
Let's look at the top mobile tracking methods with the pros and cons outlined for each.
Fingerprinting technologies anonymously match a combination of attributes to a device to arrive at a high statistical probability that two events with a similar fingerprint are from the same device. For example, if someone from a specific device taps an ad and then a similar device profile registers an app install 60 seconds later, the probability those two events were the same device is extremely high.
Pros: The whole process happens in about 300 milliseconds and is transparent to the user. Apple probably won't reject it since the tracking process is out of their control.
Cons: The approach carries a risk of generating duplicates. Over a long period of time, fingerprinting can produce discrepancies. However, you can see a high percentage of accuracy (~94 percent) if you only fingerprint for a short period of time.
Apple's Unique Device Identiﬁer (UDID) was the standard mechanism for tracking installs across mobile web and mobile apps for iOS. Due to privacy concerns, Apple depreciated access to UDID in applications, resulting in apps using UDID being rejected from the App Store. Since then, marketers have been looking for alternatives to track their app performance.
OpenUDID is a free, open source UDID initiative that uses a copy-and-paste feature in iOS to share data between applications in order to store a unique identifier. The goal of OpenUDID is to provide a replacement for UDID which remains persistent on the device, is accessible and unique across apps, and is backward and forward compatible with existing UDID.
Pros: OpenUDID give users the option to opt out. If OpenUDID is integrated into a tracking SDK, ad click events and app installs can both be logged with an associated OpenUDID to allow for accurate tracking of unique devices. It can be removed or regenerated and is therefore much better aligned with privacy frameworks such as those detailed by the IAB and MMA.
Cons: No clear concern for using OpenUDID as a tracking option.
Media Access Control (MAC) addresses are unique to a hardware device and have become a common replacement for the deprecated UDID. In some cases, MAC address-based tracking solutions encrypt or hash the MAC address in an attempt to make it anonymous.
Pros: One beneﬁt of using MAC addresses for tracking is the similarity to UDID tracking. A MAC address can be identiﬁed across applications and mobile web, allowing for accurate tracking of install events. It's unique to every single device, just like the UDID so it would be an easy one-to-one replacement.
Cons: A hashed MAC address is no better than a UDID since it cannot be erased the way a cookie can on a browser. This may be a concern if Apple decides to deprecate MAC address because of similar reasons for deprecating UDID.
Open Device Identiﬁer Number (ODIN) outlines platform-specific approaches for generating reusable device identifiers. ODIN tracking is anonymous in that it is unique to the device without revealing data about the originating device make, model, or other data.
Pros: ODIN provides standardization with an identiﬁer that could be used across iOS, Android, and Windows Mobile.
Cons: No clear concern for using ODIN as a tracking option.
Cookie Tracking (could be deprecated soon)
Cookie tracking sets a ﬁrst party cookie in Safari on iOS. Cookies on a mobile device are the equivalent of their counterparts in desktop browsers, though they are more limited by default mobile device security settings. Cookies cannot be shared across apps or shared between a mobile app and the mobile web. The workaround to pair an app install to an ad click is a brief redirect to Mobile Safari on application launch, which allows the cookie to be read.
Pros: This method mimics what advertising networks have been doing for years on the desktop web to track users through cookies.
Cons: Apps force the user to open a Safari browser window when they first open the app or click on an ad. There's also a possibility of inaccurate attribution in a scenario where the user clicked two diﬀerent ads prior to app install. Also, cookie data is lost anytime either the browser cache or HTML5 local cache is cleared. The app store has already started to reject apps because they are using first party cookies for tracking.
TRUSTed Mobile Ads
TRUSTed Mobile Ads platform is designed to allow users the ability to easily opt out of tracking.
While it's not a tracking mechanism itself, TRUSTed Mobile Ads is an important consideration in the mobile tracking ecosystem because it's platform increases user (and marketing!) confidence and establishes a foundation that allows businesses to effectively implement new mobile technologies.
Tracking SDKs that integrate TRUSTed Mobile Ads with applications, will allow users control over how much of their data can be tracked.
Apple IFA and IFV
The Advertising Identiﬁer (IFA) is a non-permanent, non-personal, device identiﬁer apps can use for tracking. The Identiﬁer for Vendor (IFV) is an identiﬁer used to associate apps that come from the same vendor on the same device. A diﬀerent IFV value is returned for apps on the same device that originate from diﬀerent vendors, and for apps on diﬀerent devices regardless of vendor.
Pros: Unlike UDIDs, IFA is located in a device's settings rather than in the hardware. IFA can track you all the way through to purchase or app download giving advertisers more data to refine their ads and targeting. If users take the time to limit tracking, the information will still be sent to advertisers as a flagged notice and advertisers should respect users' wishes.
Cons: There is currently no big concern. However, this is a solution for iOS only. If an advertiser wants to market across multiple platforms, they have to implement different tracking systems rather than a universal method.
Android Referrer is a standard method for tracking app download provided by Google. The Referrer provides a method that allows advertisers to pass tracking parameters to the Google Play Store, which then in turn passes these parameters back to the source at the time of app download. The Android Referrer provides reliable closed-loop attribution.
Pros: This method is standard for all Android devices. The Android Referrer provides reliable closed-loop attribution.
Cons: Supported only on Google Play so if the app runs on other platforms, you need to implement a different type of tracking on the others.
It's difficult to determine which technology to implement because many of the options have trade offs, and support for each technology can greatly vary by ad network and platform. Tracking is only one aspect to consider when researching a mobile app vendor.
Here's a helpful comparison chart to help marketers compare mobile app vendors.
Are you currently marketing a mobile app? Which tracking method did you choose? What additional pros and cons would you add to these methods?
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