Understanding Web Site Statistics

Essentially, your web site is on a networked machine that waits for connections from the outside world. Your web server waits for requests to come from a visitor's browser and serves certain documents to the browser as requested.

To communicate, the server and the browser use specific protocols that allow them to understand each other. A typical request would work like this:

1. The user types in a URL
2. The browser, typically Internet Explorer or Netscape, connects to the web site server and requests the specified document.
   
3. The web server handles the request and sends out a response:
   
   1. If this document exists, the web server delivers it,
   2. If it does not exist or if access is not permitted, the web server sends back an error message instead.

The document delivered as an answer to this request may contain references to other objects, such as graphics, audio files, or scripts. The browser requests all of the objects referenced on the current page from the server.

Every response from the server gets logged in the server's logfile. Since the server was hit by a request, such a response is called a Hit.

Often, web browsers will send out conditional requests asking for documents only if they have been modified since the last visit to a site. These conditional requests are logged by the server, but if no changes have been made there may be no file transfer. In addition to caching by web browsers such as Netscape and IE, there may be caching mechanisms put in place by your ISP or corporate network. These are typically referred to as proxy servers. Proxy servers reduce network load especially where a large number of users are involved. AOL uses caching extensively to reduce network load where millions of users may be visiting the same web sites.

Many statistical programs show hits, file transfers, pageviews, unique URLs, sites and sessions. Others show KB transferred and information such as Code 304, Code 404 or Code 200. Here are a few definitions that should shed some light on your traffic statistics.

Hits
Any response a server sends to any browser.

Files or Code 200
Any successful response to a request for any type of file. This includes image files as well as HTML or other web documents.

Code 304
A server response that indicates a document has not been updated since the last visit. A local, or cached copy is then used by the visitors browser and no file transfer takes place.

Pageviews
Pageviews are all files which represent actual documents such as those ending with the .htm, .html or .txt suffix.

Code 404
A server response that indicates a file was not found and could not be served.

KB Transferred
Generally refers to the actual amount of data served in Kilobytes.

Unique URLs
The number of unique web addresses that have requested information from the server. Visitors returning from the same URL may not be counted and URLs that represent all users from a corporate network or ISP may not necessarily be counted.

Sessions
The number of unique hosts requesting information from the web server during a given period. Depending on your statistical software unique sessions could be anywhere from 1/2 hour to 1 day. Sessions is generally the best indicator of the number of users that visited a site regardless of the number of pages they looked at or files they downloaded.

It should be noted that many of the "hit counters" that are available count only the number of times that counter script is loaded regardless of the URL, or the time window and typically give inaccurate and inflated indications of web site traffic. Additionally, these counters give results only for the pages that they are on and disregard other pages within a site. They can be useful, but their results should be taken with a grain of salt. Professional log file analysis software should be implemented for a more accurate indication of site traffic. There are many third party software and host implemented solutions available with a large number of them being free or very reasonably priced.

For definitions of terms used in this article on please see our Dictionaries and glossaries.

For a directory of site features including third party counters and statistical scripts please see our resources for do-it-yourselfers.

For a directory of Professionals that can help you build your online community please see our directory of professionals.