I am sometimes asked by work colleagues and clients for comparisons between different web analytics products – Which product should be used and how do they differ in the way that they compile data? As a result, I discuss below the differences between dynamic tracking and log file analysis and the pros and cons of implementing each method.
Dynamic tracking products, such as Google Analytics, may produce different traffic statistics compared to a log file analysis tool. This is because Google Analytics uses client-side code to gather information, whereas most log file analysis products contain only server-side information. By gathering data directly from user browsers rather than log files generated from web servers, the results can differ dramatically.
Below is only a basic summary of the two methods as there are many more features of web analytics that could be discussed in more detail but this will give you a general understanding as to how different methods are used.
Alternatively, log file analysis products use a visitor’s IP address to track user sessions. This can be very unreliable since two or more visitors can share an IP address and it also makes it more difficult to determine whether a user has previously visited the site.