Starting this month, Google is making changes to the way it captures and reports on conversions in AdWords in response to Apple’s coming Safari update.

In June, Apple introduced Intelligent Tracking Prevention, an initiative aimed at limiting third-party trackers from capturing cross-site browsing data, in the next version of Safari, coming out this fall. The move has implications for ad performance tracking for Google and others. On Thursday, Google sent an email to AdWords advertisers outlining changes it is making in response to Intelligent Tracking Prevention.

What is Intelligent Tracking Prevention?

In short, with ITP, third-party cookies that are determined to be able to track users across sites can only be used for 24 hours from the time a user visits a website via Safari. After 24 hours, the third-party cookies can only be used for log-in purposes. The cookies are purged entirely after 30 days.

This means that unless a user converts within 24 hours of last visiting an advertiser’s site after clicking an AdWords ad, for example, the conversion attribution will be lost. With Safari accounting for nearly 50 percent of mobile web traffic share in North America, ITP has the potential to wreak havoc on mobile ad conversion attribution.

What changes is Google making?

ITP is aimed largely at limiting pervasive retargeting practices rather than disrupting advertisers’ ability to track ad campaign performance. Google is addressing ITP with a method in keeping with Apple’s guidance around ad attribution, which states, “We recommend server-side storage for attribution of ad impressions on your website. Link decoration [ e.g., padding links with information] can be used to pass on attribution information in navigations.”

Namely, Google has developed a new Google Analytics cookie that will be used to capture campaign and conversion data from Safari in a way that conforms with ITP.

“We are updating our measurement tools, consistent with Apple’s recommendations for ad attribution, to help our customers continue to accurately measure ad clicks and conversions,” said Chi Hea Cho, a Google spokesperson via email. “These changes are designed to work for all browsers, but are timed to adapt to the new settings Apple is introducing. Our goal is to limit interruptions to our users’ experiences and to preserve our partners’ ability to evaluate their investments in digital advertising. As always, giving users choice and control of their data and how it’s used is a top priority for us.”

From Google’s email:

To help ensure conversions are reported accurately in your AdWords account, we’ll be making three changes, consistent with Apple’s recommendations for ad attribution: If you have auto-tagging enabled and a Google Analytics tag on your website, we’ll begin to set a new Google Analytics cookie on that site’s domain, which will store information about the ad click that brought a user to your site. If you have linked your AdWords and Google Analytics accounts, the AdWords conversion tracking tag will be able to use that click information. AdWords will continue to report conversions for users who have recently interacted with Google services and domains. AdWords will also use statistical modeling to estimate website conversions that could not be measured from Safari, and include them in your AdWords reporting

TL;DR — What do the changes mean?

The short version of the implications of this change:

Advertisers that have AdWords and Google Analytics accounts linked: There is no change. Google will report observed conversions from Safari as it has been doing via this new cookie. Advertisers that don’t link their Google Analytics accounts or disable the new cookie: AdWords will use modeling to account for Safari conversions that may occur 24 hours after a user last visits an advertiser’s site from an ad via Safari.

Get a daily dose of the latest Search news, tips and tactics. Sign up below. SUBMIT Note: By submitting this form, you agree to Third Door Media's terms. We respect your privacy.

How does this new cookie work?

The new Google Analytics cookie — called the _gac cookie — extends the usage of Google Analytics (GA) tracking to include AdWords conversion tracking. It will be used to store the ad click information when auto-tagging is enabled. From the support page, “Analtyics writes campaign information to the _gac cookie when a user opens a page on your site via a URL that employs AdWords auto-tagging.”

The big difference is how the cookie is handled.

Today, the conversion cookie is set on the Googleadservices.com domain, which means it is considered a third-party cookie. With this change, the new _gac cookie will be set on the advertiser’s domain, becoming a first-party cookie and acceptable to ITP. That means ad data associated with the user will remain intact for attribution and conversion reporting.

Impact on AdWords conversion reporting

To reiterate the above, advertisers that have linked their AdWords and Google Analytics campaigns will see no change because the new cookie acts as a first-party cookie and can continue recording conversion data from Safari traffic.

For those that don’t link their accounts or disable the new cookie, Google will be able to record conversion activity that occurs within the initial 24-hour period. It will use modeling based on historical conversion activity to record conversions from Safari in AdWords. Those modeled conversions will be included in AdWords conversion columns. The company says, “It may be a few days before you start seeing these conversions in your AdWords reporting.” Advertisers can opt out by updating their Google Analytics tag at any time.

Related reading on our sister site Martech Today: On Thursday, Sept 14, the major advertising industry groups responded to the Apple Safari update in an open letter. They aren’t pleased.