Products
Webtrends Analytics
Issue
What limitations do session-tracking methods definitions have?
Resolution
The following session-tracking methods define the range of options available by which visits are defined and can be totaled.
Authenticated Users
The most accurate way to count visits to a site is to require every visitor to use a unique username/password combination before entering the site. This ensures that the log file contains information that uniquely identifies every user. This information is required for the “Authenticated Users” report.
Limitations
- Due to site policies or technical limitations, it may not be possible to implement authenticated users.
- Some potential visitors may decline to visit the site if content is only available once they have logged in, and their reasons may stem from concerns over privacy or the desire not to manage yet one more set of credentials.
Cookies
Cookies are pieces of software code that reside on the hard drive of the client (or requesting) computer that contain information that identifies the computer to the server. It is recommended that these cookies be persistent cookies, which means that the same cookie stays with the visitor even after leaving the site.
Limitations
- Some visitors may refuse to accept cookies.
- Cookies can be deleted from the client hard drive. This could result in double-counting unique visitors during a period if the visitor deleted cookies between visits.
- There is no way to know if the client computer is a shared computer between many unique visitors.
IP address/User Agent
Using the IP address and user agent of the visitor bases the visit off of two potentially mutable factors. This method is recommended in situations where stronger session-tracking methods are not an option.
Limitations
- The user agent reported by the browser can be easily spoofed and changed on the fly.
- Many ISPs and organizations use dynamic ISP addressing where an IP address can be determined dynamically when a user logs in, through the use of firewalls, or by a load-balancing device.
- Some, filter all data so it comes through an intermediate proxy server. In this case, the web server sends the requests not to the individual requester, but to the proxy server of the ISP. The information is then sent on to the actual visitor, but with the source address of the proxy server. The IP can change many times during the course of a visit depending on which proxy server is making the request, which can result in multiple visits.
Example:
If visitor “A” visits a site and immediately leaves, and visitor “B” comes to the site within the time frame defined using the same source IP address/User Agent, both visitors will be counted as 1 visitor and visit.
URL/Parameter-based tracking
A unique URL or parameter are store data such as a Session ID.
Limitations
A new Session ID is generated every time a visitor visits the site, from which all visitors will appear as new visitors.