When a person comes to your website, they can be counted as a visitor multiple times.
Piwik PRO uses three mechanisms to recognize a visitor:
- Visitor ID: the ID stored in the cookie set in the visitor’s browser.
- Device fingerprint: a set of data about the visitor’s browser that allows to identify them. For example, an IP address, browser type, operating system, and more.
- User ID: a piece of additional information about the visitor that can be captured on your website. It can be a visitor’s email, username or another identifier. The user ID helps to attribute sessions to the visitor and is treated as a last resort identification mechanism, for example when the visitor has disabled cookies. The user ID tracking needs to be additionally set up.
So, when Piwik PRO can recognize a person based on the above information, he will count that person as a visitor. But in some cases, Piwik PRO won’t know that a person is the same visitor.
Here are some of those situations:
- When a person enters your website on a laptop and mobile, then they will be counted twice.
- When a person enters your website through different website browsers, then they will be counted multiple times.
- When we don’t use
Visitor ID, and base on the visitor’s fingerprint, we may count them multiple times when they change the location or workstation and the IP address changes.
Another important thing to know is that when you look at reports you may see that the number of visitors doesn’t add up as you would think at first glance.
- In week one, we had 2 visitors.
- In week two, we had 2 the same visitors.
Now when we look at a date range for week one, we’ve got 2 visitors, and for week two 2 visitors as well. But, if we take a date range of these two weeks (week one + week two), we’ve got 2 visitors (not 4 as we might think).
Piwik PRO counts (it’s a predictable counting) the number of visitors for each date range so that you could see the number that corresponds to reality the most.