Discrepancy in Visitor Numbers When Combining Segments in Adobe Analytics

[firstMarlon]

Hi everyone,

I'm encountering an issue in Adobe Analytics and would appreciate some help. I've created four segments, and the visitor numbers for each segment are as follows: 40, 60, 30, and 70. When I combine these segments into a single segment, I expect the total number of visitors to be 200. However, the combined segment shows a different number, for example, 224 visitors.

(Note: These numbers are just examples to illustrate the issue.)

Why is there a discrepancy in the visitor numbers when combining segments?

Thanks in advance for your assistance!

[bjoern__koth]

Hi @firstMarlon 

Interestingly, the numbers should typically be smaller as soon as segments start overlapping and when visitor deduplication kicks in.
I can only think of some logical conditions that could affect your audience size.

So, it would surely help if you can provide some screenshots with the segment definitions.

One last question: what do you see when you visualize your segments in a Venn diagramm? Are they mutually exclusive or do they partially overlap?

[firstMarlon]

Hi everyone, thank you for your replies!

Here is a screenshot of how the segments are built (visitor level). The actual report is similar but a lot bigger, but the logic is the same.

A, B and C are built the same just for different regions. Summing them up in a segment (Total.PNG) gives me a higher number than summing them up manually.

In a Venn diagramm they are mutually exclusive.

Best wishes from Austria!

[MandyGeorge]

That's really weird that the total is giving you a larger number than the individual ones summed up. Have you tried putting the total segment in a table, and then breaking it down by your "page url (clean)" dimension? See what the individual numbers are for the dimension items and compare those to the individual segments. That might help you identify where the traffic is coming from. 

[MandyGeorge]

Are you able to share more about how the segments are built? Are they visit or visitor level segments? Typically the total number should be smaller when you combine them, but it's hard to give definitive answers on why that's happening without knowing more about the segments themselves. 

[Jennifer_Dungan]

I agree with both @bjoern__koth and @MandyGeorge 

Seeing how you have built your segments will help us to help you. As Bjoern said, typically de-duplication should make the numbers smaller, not larger.. there must be some other logic at play here that we can't see.

[gautham_madala · Accepted solution]

The key reason you're seeing more than 200 visitors (in your example, 224) when combining the four segments is due to visitor overlap.

Here's what's likely happening:
Each of your segments (40, 60, 30, 70 visitors) represents a set of unique visitors, but some visitors may belong to more than one segment. So when you combine these segments using an "OR" condition, you're essentially saying: give me all visitors who meet the criteria for any of these segments.

Adobe Analytics does not de-duplicate visitors when showing individual segment counts — but it does de-duplicate when you combine them. Hence, the total combined count could be:

less than the sum, if there's overlap (e.g., a visitor appears in two or more segments).

more than the sum, only if you made an error in calculation or interpretation — but that's rare unless you're looking at visits or hits, not visitors.

Use the Venn Diagram feature in Workspace to visualize how segments overlap.

Build a segment combining all four using OR logic and compare it against the individual segment counts.

Try breaking it down using a Visitor ID dimension (if available), which can help reveal who is in multiple segments.

[Sukrity_Wadhwa]

Hi @firstMarlon,

Were you able to resolve this issue with the given suggestion or was this something you were able to figure out on your own or do you still need help here? Do let us know.

Thanks!