What may explain to have more unique vistors than possible?

General questions
1

Hello,
I have installed Piwik to track visitors on a an intranet. The number of possible unique visitors is known as the intranet access is limited.
What may be the reasons that the counter of unique visitors on a weelky based is more than possible ?
Example: Let say that unique visitors for the week is:
Monday:319
Tuesday: 323
Wednesday: 318
Thursday: 282
Friday:286
Saturday: 5
Sunday: 9
If I take a look to the week report, I have 973 unique visitors. (and something around 2300) on a monthly based.
It really looks like that for a same physical visitor, Piwik returns several different Visitors.
What may explain this behavior ?

2

Hi there,

See: https://piwik.org/faq/general/#faq_43

Unique visitors are determined using first party cookies stored in
your visitor browser. When a same person visits your website on two
different devices (for example their laptop and on their mobile phone)
then Piwik will detect two unique visitors.

3

Hi, Thanks, I was knowing this behavior but is there any additional issue that may lead to miscount unique visitors ?