Cookies in Display & Video 360 versus Audience Partner API

Display & Video 360 and Audience Partner API use different methodologies to count audience size. Because of this, availability numbers in the two systems are expected to be different.

  • In Display & Video 360, availability numbers are based on the number of unique cookies in the specified audience lists that have sent bid requests to Display & Video 360 during the appropriate window of time (which is either the time period of the Inventory Availability report or the total number of days your line items will be active). Please note:

    • Display & Video 360 only counts cookies that are "reachable", which means actively browsing on sites and generating ad calls to Display & Video 360.
    • Again, Display & Video 360's availability numbers are extrapolated from sampled bid requests, so the counts may differ from availability numbers based on the raw, unsampled count of cookies.
  • In Audience Partner API audience size is based on the number of unique cookie IDs in an audience list at the current time (i.e. the raw, unsampled count of all cookies).

Which system should I trust for cookie data?

The short answer is, Display & Video 360.

In most situations, Display & Video 360's Inventory Availability report should give you a reasonable estimate of the number of impressions and cookies you can expect to reach on Display & Video 360. The exception to this is any newly created, synced, or deleted audience lists may cause availability numbers to be lower or higher than in reality because of the delay in how long it takes Display & Video 360 to process new availability data.

Audience Partner API's counts are good for knowing if an audience list has cookies or not and if it's growing or shrinking in size.

Display & Video 360's count of "reachable" cookies (based on actual user activity) is more useful than the count of raw cookies, which may or may not be reachable or active.


Is there a drop-off when audiences are shared from other Google Marketing Platform products to Display & Video 360?


Since these audiences aren't actually copied or transported into Display & Video 360, there won't be any differences in audience between the products. Put another way, when you share audiences between Google Marketing Platform products, you are simply sharing access to the same audience list via Audience Partner API.

However, remember that Display & Video 360 calculates availability numbers differently from Audience Partner API, so you can expect Display & Video 360's available impressions and cookies to differ from systems that calculate audience size based on raw cookie IDs.

If Display & Video 360 counts only the "reachable" cookies, can Display & Video 360's count ever be higher than the raw count?

For a single day, no, Display & Video 360's number of cookies will never be higher than the raw counts from Audience Partner API. For example, if you create an Inventory Availability report for a single day (e.g. yesterday), you'll notice that Display & Video 360's number of cookies are typically much lower than the raw count of available cookie IDs that you'd see in Audience Partner API.

However, if you create an Inventory Availability report that spans multiple days, you may see availability numbers that are higher than the numbers from Audience Partner API. This is because Display & Video 360 considers cookies that were active at any point in the date range of the report, rather than the cookies that are active right now (which may include cookies that are deleted or expired). Please note:

  • Display & Video 360 tries to prevent double-counting deleted or expired cookies, but these efforts aren't always perfect.
  • Although Display & Video 360 doesn't directly check to see when cookies expire, Display & Video 360 does filter out cookie IDs that aren't sending ad activity in the date range of a given report. For example, a cookie that expired yesterday would not be associated with bid requests Display & Video 360 sees today, so Display & Video 360 wouldn't include that cookie ID in its count for today's date.
How can I tell when an audience from another Google Marketing Platform product was added to Display & Video 360?

Starting inside an advertiser, navigate to the Audiences page, click the audience you're interested in, then click the History in the left-side menu.

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