Why Doesn’t Google Analytics and Web Server Log Files Reports?
At a high level, the simplest explanation is that Google Analytics uses client-side code to gather information, whereas most log file analysis tools only process server-side information. This is an important distinction and is a key reason for differences in data, but there’s more to the story. Typically, the difference is mainly caused by the visitor tracking method used.
A web log analysis tool typically tracks website visitors by IP addresses & user agents or session IDs. The data will show everything – regular visitors, visitors that block Google Analytics tracking code, and traffic from non-visitors like robots & spiders. You can make the argument that a web log analysis tool provides a more accurate picture of what’s actually happening on your website.
So what does this mean?
It means it’s not useful to compare data between two analytics tools if the tracking methods are different because each tool provides a different look at your website. But therein lies the opportunity – instead of only using one solution, why not use both?
Google Analytics + Web Log Analysis
Google Analytics provides a lot of useful data, and web log analysis tools li
Additionally, Google Analytics is able to simultaneously send tracking data to the GA data collectors and to your web server’s log file with the setLocalRemoteServerMode(); function. This means you can keep an on-site copy of Google Analytics data and combine it with the “extra” reports you get from a web log analysis tool.
If use Universal Analytics, you can also keep a local copy of GA tracking data.