6.1 Log File Analysis

The main advantages of log file analysis over page tagging are:

• Web servers normally produce log files, so the raw data are already available. No changes to the website are required.

• The data is on the organization’s own servers and is in a standard, rather than a proprietary, format. This makes it easy for an organization to switch programs later, use several different programs, and analyse historical data with a new program.

• Log files contain information on visits from search engine spiders. Although these MUST NOT be reported as part of user activity, it is useful information for search engine optimization.

• Log files require no additional DNS lookups. Thus, there are no external server calls which can slow page load speeds or result in uncounted page views.

• The web server reliably records every transaction it makes, including items such as serving PDF documents and content generated by scripts, and does not rely on the visitor’s browser.