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3rd ID


Level 1

Is Adobe 3rd ID the same as device name?

2 Replies


Community Advisor

We might need more details to understand your query here. If it is related to how unique visitors are counted, then this the order:

Identifying Unique Visitors

The method for identifying unique visitors among multiple contexts includes a prioritized sequence to ensure accuracy in this determination. The following table shows this prioritized sequence:

Order used Query parameter (collection method) post_visid_type column value Present when
1vid s.visitorID0s.visitorID is set.
2aid  s_vi cookie3Visitor had an existing s_vi cookie before you deployed the Visitor ID service, or you have a Visitor ID grace period configured.
3mid AMCV_ cookie set by Identity Service5Visitor’s browser accepts cookies (first-party), and the Identity Service is deployed.
4fid fallback cookie on H.25.3 or newer, or AppMeasurement for JavaScript4Visitor’s browser accepts cookies (first-party).
5HTTP Mobile Subscriber header2Device is recognized as a mobile device.
6IP Address, User Agent, Gateway IP Address1Visitor’s browser does not accept cookies.

For information on how unique visitors are reported, see Unique Visitors in Analytics.


You might also want to look at this documentation to see what each query parameter/property in the payload send to adobe analytics correspond to:


Also anything between c.a. and .a.c are adobe reserved variables that should be automatically mapped to some reports may they be mobile reports, video reports and so on.


Employee Advisor

The 3rd Id probably denoted something about the type of activity. Don't think it was the device ID/name. But it is largely ignored and not used anymore. 


This doc on A4T reporting also tells us to ignore it 🙂