Logfile analysis vs page tagging

Both logfile analysis programs and page tagging solutions are readily available to companies that wish to perform web analytics. In many cases, the same web analytics company will offer both approaches. The question then arises of which method a company should choose. There are advantages and disadvantages to each approach.

Advantages of logfile analysis

The main advantages of logfile analysis over page tagging are as follows.

• The web server normally already produces logfiles, so the raw data is already available. To collect data via page tagging requires changes to the website.
• The web server reliably records every transaction it makes. Page tagging relies on the visitors’ browsers co-operating, which a certain proportion may not do (for example, if JavaScript is disabled).
• The data is on the company’s own servers, and is in a standard, rather than a proprietary, format. This makes it easy for a company to switch programs later, use several different programs, and analyze historical data with a new program. Page tagging solutions involve vendor lock-in.
• Logfiles contain information on visits from search engine spiders. Although these should not be reported as part of the human activity, it is important data for performing search engine optimization.
• Logfiles contain information on failed requests; page tagging only records an event if the page is successfully viewed.

Advantages of page tagging

The main advantages of page tagging over logfile analysis are as follows.

• The JavaScript is automatically run every time the page is loaded. Thus there are fewer worries about caching.
• It is easier to add additional information to the JavaScript, which can then be collected by the remote server. For example, information about the visitors’ screen sizes, or the price of the goods they purchased, can be added in this way. With logfile analysis, information not normally collected by the web server can only be recorded by modifying the URL.
• Page tagging can report on events which do not involve a request to the web server, such as interactions within Flash movies.
• The page tagging service manages the process of assigning cookies to visitors; with logfile analysis, the server has to be configured to do this.
• Page tagging is available to companies who do not run their own web servers.

Economic factors

Logfile analysis is almost always performed in-house. Page tagging can be performed in-house, but it is more often provided as a third-party service. The economic difference between these two models can also be a consideration for a company deciding which to purchase.

• Logfile analysis typically involves a one-off software purchase; however, some vendors are introducing maximum annual page views with additional costs to process additional information.
• Page tagging most often involves a monthly fee, although some vendors offer installable page tagging solutions with no additional page view costs.

Which solution is cheaper often depends on the amount of technical expertise within the company, the vendor chosen, the amount of activity seen on the web sites, the depth and type of information sought, and the number of distinct web sites needing statistics.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.