There are quite a number of website statistical packages available and Google Analytics generally reports the lowest number of visitor traffic. Is it because Google Analytics is correct and the others are wrong? Or is Google Analytics just missing some of the traffic?

There are two types of web analytics technologies in use today.

1. Log File Analysis: This includes analytics such as Webalizer or AWstats. With these the web server records all transaction about visitors. Because the log files are on the web server, the data is logged no matter what browser or what settings the visitor is using.
2. Page Tagging involves a code being placed directly on the web page and reporting back to the analytics package the visitor data. This includes analytics such as Google Analytics and Statcounter. Page tagging works by using JavaScript and cookies (Google Analytics) or JavaScript / cookies (Statcounter).

So what causes the differences?

1. If the user has JavaScript or cookies disabled, Google Analytics will not report visitor traffic. It is estimated that  8-10% of users have JavaScript turned off.
2. Google Analytics will under report if the reporting is blocked by security software like Norton.
3. IP address based analytics will report the same person over and over if they use dial-up. This is because dial-up shows a different IP address with each connection. Since Google Analytics is cookie based, it will report a lower number.
4. Google Analytics has a very good ability to separate bots and spiders from actual visitors. Other analytic packages over report visitor traffic that are actual bots and spiders.

The true measure of visitor traffic is generally somewhere in the middle and is more than what Google Analytics reports and less than what the other web analytics reports. Use your analytics to measure trends and understand that the actual number of visitors may be somewhat different.

Related posts:

1. Not Seeing AdWords Data in Your Google Analytics?
2. Using Google Analytics To Chart Success
3. Using Google Analytics To Chart Success #2 – Setting Goals
4. Building Visitor Traffic
5. User Persona: Developing a Website Visitor Profile