Constraints on Aggregation Reporting data
Understand the data constraints, requirements for destinations and origins, and the impact on schedules.
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To plan your Attribution Reporting strategy, you'll need to know the constraints enforced by the API, including how much data can be collected for each report.
Event-level reports
The following sections on click and view events describe features and limitations to keep in mind.
navigation
source)
Click (source_event_id
(ad-side information) can be up to 64 bits, large enough to be used as a unique identifier.trigger_data
(conversion-side information) is up to 3 bits; that is, it should be an integer between 0 and 7.- Up to 3 conversions can be attributed to a given source (ad click or view event).
- Noise is applied to reports in the form of a randomized response. The correct conversion count can be recovered using a script.
- Noise is applied with a 0.0024 (0.24%) probability in the current Chrome code.
- Reports are sent with a delay of between 2 and 30 days; the exact mechanism for views and clicks varies. See details in Report scheduling for event-level reports.
event
source)
View (source_event_id
(ad-side information) can be up to 64 bits, large enough to be used as a unique identifier.trigger_data
(conversion-side information) is up to 3 bits; that is, it should be either 0 or 1.- Up to 1 conversion can be attributed to a given source (ad click or view event).
- Noise is applied to reports in the form of a randomized response. The correct conversion count can be recovered via a script.
- Noise is applied with a 0.0000025 probability (0.00025%) in the current Chrome code.
- Reports are sent with a delay of between 2 and 30 days; the exact mechanism for views and clicks varies. See details Report scheduling for event-level reports.
Aggregatable reports
The following list describes limitations to keep in mind.
navigation
source) and View (event
source)
Click (The total values of all the buckets attributed to a source should be at most 65536. For example, let's say:
The first conversion for a source is:
"campaignCounts": 32768
"geoValues": 1664
The second conversion for that same source is:
"campaignCounts": 12323
"geoValues": 1664
Note that there can be more conversions.
So, in the example,
total = 32768 + 1664 + 12323 + 1664
Keep in mind that:
- The total must be under 65536, as mentioned earlier.
- The maximum number of aggregation keys allowed in the source registration is 50. This is also the maximum number of contributions per aggregatable report.
- Noise is applied in the aggregation service.
- Reports are sent with a random delay between 0-1 hours.
All reports
- For a given user, within all unexpired sources, there can be a maximum of 100 different destinations (typically, advertiser sites, or sites where conversions are expected to take place). Unexpired sources are ad clicks or views to which a conversion can still be attributed; that is, for which
expiry
has not yet been exceeded. In other words, the unique destination limit for attribution sources is covered by unexpired sources, instead of pending sources. - 100 attributions per {source site, destination, reporting origin} (typically {publisher, advertiser, ad tech}) can be scheduled over 30 days.
- 100 unique reporting origins (typically ad techs) can register sources per {publisher, advertiser} per 30 days. This counter is incremented for each ad click or view (source event), even those that are not attributed.
- 10 unique reporting origins (typically ad techs) can send reports per {publisher, advertiser} per 30 days. This counter is incremented for every attributed conversion.
- Prior to Chrome 108, this limitation was as follows: For a given user, within all unattributed sources—ad clicks or views for which no conversion has been attributed yet—there can be a maximum of 100 different destinations (typically, advertiser sites, or sites where conversions are expected to take place).
Next steps
For more on the timing of reports, review:
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