In general, the number of Customer IDs in the Segment Manager is lower than the number of "Visitors" in Analytics.
Number of Customer IDs in the Segment Manager:
Number of "Visitors" in Analytics:
The reasons for that are:
- The Segment Manager output (i.e., the table and the number of users) only contains users whose last visit happened within the analysis period. In contrast, the "Visitors" metric in Analytics counts every user who visited the page within the analysis period.
Example: Suppose you create an analysis on Jan 31 and choose the period from Jan 10 to Jan 20 as analysis period. If a user visits the website on Jan 15 (within the analysis period) as well as on Jan 27 (after the analysis period), his Customer ID is not taken into account for this Segment Manager analysis because his last visit did not happen within the analysis period.
- In the Segment Manager, there is a automatic data cleanup which follows distinguished rules. This avoids accumulation of data that is not relevant. Therefore, particular Customer IDs are not part of the Segment Manager analysis; nevertheless, each of the corresponding visitors is counted in the "Visitors" metric (as any other visitor). The automatic cleanup rules are described in the Training Chapter Segment Manager – User-centric Data.