Date range discrepancy

[lauraa84411195]

I am somewhat new to AA and wonder is someone can help with the following query?

I have a report where I am measuring unique visitors to group of pages from 3 sep to 31 jan. When I run a report for this complete date range I get a figure of 27,117.

However when I split the date range from 3 sep to 2 dec and 3 dec to 31 jan i get: 7,712 & 20,229. In theory you would expect that these two figures should add up to 27,117 but they obviously don't.

Has anyone come across this or is there something obvious with the date range that I'm doing wrong?

Thanks.

[KristiB1 · Accepted solution]

Hi there,

this is most likely because you have visitors who feature in both time periods.  E.g. Someone has visited on Dec 1, and then again on Jan 1.  They will be counted in each date range.

So therefore you cannot simply add two date ranges for unique visitors to get the total.  Your first report, from Sep 3 to Jan 31 will give you the total unique for that time period.

It almost never makes sense to add together unique visitors.