Duplicate Unique Visitors for MID

[alexanders58976]

Hello,

Why does some unique Visitor MID values show 2 unique visitors in Analysis Workspace? Believe that a given MID should always show 1 Unique Visitor?

Would appreciate suggestions on how this should be fixed.

Thank you.

[sspatra25]

Hi

Even i am seeing the same result. When i analyzed further i see that there are two different browsers which customer used. I think there is probably a sync happening where Adobe is able to resolve both the unique visitor to one experience cloud id. Ideally they should consider them as unique visitor, but, i guess it is not happening.

[Andrey_Osadchuk]

Alexander, can you please share a screenshot of the same table with a few additional metrics?

• Visitors MID Instances
• Visitors with Experience Cloud ID

Also please share the settings of the eVar75 and the code (or processing rule) that is used to set the value.

Do you use s.visitorID in the implementation?

[alexanders58976]

Hi Andrey,

Sure, here is a screenshot with the the additional requested metrics:

This is the code setting that would populate eVar75 within the s_doPlugins function:

var ec_id = s.visitor.getMarketingCloudVisitorID();

if (ec_id !== '' && typeof ec_id !== "undefined") {

    s.prop75 = visitor.getMarketingCloudVisitorID();

    s.eVar75 = "D=c75";

} else {

    s.prop75 = "no MID";

    s.eVar75 = "no MID";

}

We aren't using s.visitorID in the implementation.

Do you know why row 5 shows an MID with the value '1' under the Visitors with Experience Cloud ID metric but '3' under Unique Visitors?

Thank you in advance.

[Andrey_Osadchuk · Accepted solution]

It's very interesting! I have a few hypnotises but it makes sense to address this to ClientCare to get a clarification faster

- Maybe this is because the visitor was identified with one of the fallback identification methods as explained in the documentation here: Identify unique visitors

- Maybe because of how the grace period of EC ID works

Some more questions for you:

- how many days are included in the date range?

- when did you begin a transition to Experience Cloud ID?

- did you do anything for a custom grace period activation?

- what is the eVar expiration?

===

It would be interesting to look at another modification of the table. If you can, please add one more column with Unique Visitors and under this metric add the segment as follows:

• Show Visitor
  • Visitor MID (v75)  IS GREATER THAN (DISTINCT COUNT)   1

[alexanders58976]

Hi Andrey,

My colleague contacted Client Care but we weren't able to determine the precise cause unfortunately.

The date range is Aug 1 - Aug 22 of this year.

The eVar expiration is 'Hit'. The additional column that you requested has been added:

In Workspace, I don't believe there is way to see the identification method that was used (this could have been helpful) and I don't believe that we did anything for a custom grace period activation. We have been using the Experience Cloud ID for several years.

We use the Tealium TMS and have several profiles (different site sections) populate this report suite. Maybe its something to do with that?

I see 2 New Visitors for a given MID and I'm not sure why:

Thank you.

[Waqas_Rafiq]

Hi alexanders58976719​,

Is Adobe Analytics implemented with first party cookies?

option 1: If it isn't, you could try to break down the mcvids with browser to see if it's related to safari browsers only. If this is not purely safari browsers but all over the place, then it might be worth looking at this option:

option 2: I have seen issues similar to your one which was not related to any firstparty cookie issue, here we saw that when users clicked through from one domain to another subdomain, the mcvid would sometimes get reset (was on several calls with the adobe engineering team, which didn't understand what was going on either), our workaround was to append the visitorid to the url and then have the code on the subdomain pick it up.

p.s the above are just some ideas for you to go further with  

Either way, I would probably look into option1 regarding first party cookies (everything you need is documented here: First-party cookies )

[Alexis_Cazes_]

I think the issue is linked to the following statement:

We aren't using s.visitorID in the implementation.

Please read the following: Identify visitors

Adobe has an order in which it assign a visitor ID if more than one are present:

Analytics Visitor IDs 

There are several ways a visitor can be identified in Analytics (listed in the following table in order of preference):       

Order Used	Query Parameter (collection method)	post_visid_type column value	Present When
	vid (s.visitorID)	0	s.visitorID is set.
	aid (s_vi cookie)	3	Visitor had an existing s_vi cookie before you deployed the Visitor ID service, or you have a Visitor ID  grace period  configured.
	mid (AMCV_ cookie set by Identity Service)	5	Visitor's browser accepts cookies (first-party), and the Identity Service is deployed.
	fid (fallback cookie on H.25.3 or newer, or AppMeasurement for JavaScript)	4	Visitor's browser accepts cookies (first-party).
	HTTP Mobile Subscriber header	2	Device is recognized as a mobile device.
	IP Address, User Agent, Gateway IP Address	1	Visitor's browser does not accept cookies.

In many scenarios you might see 2 or 3 different IDs on a call, but Analytics will use the first ID present from that list as the official visitor ID, and split that value across the  post_visid_high  and  post_visid_low  columns. For example, if you are setting a custom visitor ID (included in the "vid" query parameter), that ID will be used before other IDs that might be present on that same hit. 

In your case if you set s.visitorID the Unique Visitors metric will increment only if s.visitorID value changes. Mid value will not be used to indentify the unique visitor. The best way to confirm that is to extract the raw data using data feed or ask clientcare to extract you a day worth of data and ask fo these columns:

post_visid_type (see table above as it will return only the integer)

cust_visid

mcvisid

visid_high

visid_low

post_cust_visid

post_mcvisid

post_visid_high

post_visid_low

prop75

post_prop75

post_evar75

Focus on one of the value in either post_prop75 or post_evar75 and I will bet that you will see post_visid_type=1 and cust_visid will change twice. Either you have a section that the user is not logged in  so you do not send same s.visitorID or multiple user use same computer and keep same AMCV_ cookie so same MID but s.visitorID will change.

[alexanders58976]

Hi Alexis,

The issue appears to be that for some reason the post_visid_high and post_visid_low change for a given mid (shown in the column post_prop75) as the fourth hit:

A change in the post_visid_type can be seen from 5 (mid) to 3 (aid) for some reason for the same mid.

Please let us know if you can help us understand why this is happening and how to resolve this.

Thank you.

[Alexis_Cazes_]

we wil need to see more of the data to figure out exactly what is happening.

Has the specific visitor switched domain during this visit ? Is it the same user_agent and/or IP ?