Updates to iOS 14 campaign measurement

As a result of Apple’s App Tracking Transparency (ATT) policy changes, you will see some updates to the way we report and measure conversion information for ads serving on iOS 14 traffic. This article outlines how product changes may affect you as a Google Ads advertiser. Most advertisers will not be affected.

You can read about how we’re preparing our partners for Apple’s iOS 14 policy updates.

ATT impact on Google Click ID, website, and offline conversions

When Apple’s ATT policies take effect, we will no longer send the Google click identifier (GCLID) for iOS 14 traffic coming from ads on a handful of Google apps. Traffic from other Google sources will not be affected and will continue to include GCLIDs.

How will it affect me?

Some Google iOS apps currently use information (such as Apple’s IDFA) that would require ATT. Once Apple’s ATT policies go into effect, Google will no longer use that information, and therefore will not show the prompt in those apps, in line with Apple’s guidance.

As a result, you may see a decrease in GCLIDs in your landing page URLs for traffic originating from affected iOS apps. For impacted traffic only:

  • The &gclid={GCLID} will not be appended to ad clicks and the {gclid} ValueTrack parameter will be set to empty text “”.
  • You may see a decrease in reported website conversions.
  • You may see a decrease in reported offline conversions (imported from clicks).

What Google is doing to help

Starting in March 2021, we will introduce a new URL parameter to help comply with Apple’s policies and help you measure the results of your ads on iOS. 

This new parameter will help you attribute conversions back to your ad campaigns and work with conversion modeling to give you more accurate measurement on iOS.

To support this new parameter, the global site tag (gtag.js), Google Tag Manager (gtm.js) and Google Analytics (analytics.js) with a linked Google Ads account, will set a new first-party cookie on your domains by default. That will attribute conversions back to ads subject to ATT policies. 

As always, you can opt-out of first party cookie tracking at any time by disabling conversion linking in your respective configuration.

Preparing for iOS 14 changes

We recommend you prepare for this change with the following actions:

  • Ensure that you have the global site tag (gTag.js and/or Google Tag Manager) properly implemented on your site.
  • While most advertisers won’t need to change their website, a small percentage may need to allow arbitrary URL parameters on their website in order to ensure continuity of campaign measurement.
Note: This article will be updated to keep you informed on best practices related to iOS 14 changes. Please visit this page in the coming weeks for the latest information.

Bidding considerations for impacted campaigns

Campaigns using Smart Bidding will continue to set bids based on the most accurate measurement available. However, we recommend that you prepare for the above changes by closely monitoring the performance and delivery of all campaigns serving on iOS traffic and, if necessary, make adjustments to budgets and Smart Bidding CPA or ROAS targets to help you achieve your goals. For example: If you would like to increase spend, you can raise CPA targets or lower ROAS targets as needed.

ATT impact on app deep-link conversions

Note: If you use Google Ads to promote your iOS app, you can read Best practices for iOS App campaigns.

If your ads deep link users into your apps on iOS 14, you may also see fewer in-app conversions as Apple’s ATT policies go into effect. In reporting, we will be rolling out solutions to ensure you can continue to get the most accurate in-app measurement on iOS.

Preparing for iOS 14 changes

We recommend you prepare for this change with the following actions:

  • Stay up to date on the latest iOS 14-related information from your App Attribution Partner and/or upgrade to the latest version of Google Analytics for Firebase to ensure that your SDK supports Google’s conversion measurement on iOS.
  • While most advertisers won’t need to change their website, a small percentage may need to allow arbitrary URL parameters on their website in order to ensure continuity of campaign measurement.
  • If you use Manual CPC bidding, avoid making CPC bid adjustments (to account for the iOS reported conversion drop) until reported iOS in-app conversions normalize.
Note: This article will be updated to keep you informed on best practices related to iOS 14 changes. Please visit this page in the coming weeks for the latest information.

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