A Glossary of Site Statistics

During the most recent association meeting, statistics were mentioned for the "official"  BLMH website, including "hits". I was asked what that statistic means and here is a brief explanation, and some additional data on meaningful statistics used for gauging the visitors to websites.

There are several ways to measure visitors to a website. As is the case with most statistics, these are sometimes quoted and have various uses. Different tools use differing methods of measurement.

To provide some indication of the statistics available, here are some actual statistics for one of my sites, which is non-commercial in nature. A glossary is provided after the statistics:


Site Report - Date Range: 1/20/2010 to 1/26/2010  

Report Summary
  Total Visitors 117
  Total Pageviews 167
  Total Hits 334
  Total Bytes Transferred 13.6M

  Average Visitors Per Day 16
  Average Pageviews Per Day 23
  Average Hits Per Day 47
  Average Bytes Transferred Per Day 1.95M

  Average Pageviews Per Visitor 1
  Average Hits Per Visitor 2
  Average Bytes Per Visitor 116,723
  Average Length of Visit 405sec



Glossary of Terms
Hits
A "hit" is simply any request to the web server for any type of file. This can be an HTML page, an image (jpeg, gif, png, etc.), a sound clip, a cgi script, a pdf file and many other file types. An HTML page can account for several hits: the page itself, each image on the page, and any embedded sound or video clips. Therefore, the number of hits a website receives is not a valid popularity gauge, but is rather an indication of server use and loading.


Visitors
A Visitor is defined as a series of hits from any IP address or host separated in time by no more than 30 minutes. This definition makes several assumptions:

• A hit from the same IP address in under 30 minutes is probably the same person
• A hit from the same IP address separated in time by more than 30 minutes is likely to be a different person, and is counted as such

However, a "visitor" is not necessarily a unique person. It is not a unique IP address or host name. Unless cookies are used, it is not possible to determine these things precisely from a web server's log files. This is because many of the largest internet access/service providers recycle IP addresses out of necessity, because they have so many members. Therefore, "Visitors" is defined according to an industry-standard formula that is reasonably accurate, and will give numbers close to the actual figure for virtually all websites.


Pageviews
A "page" is defined as any file provided by a web server that would generally be considered a web document. This includes HTML pages (.html, .htm, .shtml), script-generated pages (.cgi, .asp, .cfm, etc.), and plain-text pages. Image files (.jpeg, .gif, .png, etc.), sound files (.wav, .aiff, etc.), video files (.mov, etc.), and other non-document files do not count as pages. Each time a file defined as a page is served, it is registered as a "Pageview". On my sites, each page registers separately in this statistic. I know how many views each page generated and therefore I know which pages are the most popular with visitors.



Length of Visit

The time users spend on a site is an indication of how useful and compelling they find the content to be.  This statistic varies based on the tools used to generate it. On my site, this statistic shows how much time visitors are, on average, spending on the site.  



Bytes (Transfer / Bandwidth)
A "byte" is a unit of information transferred over a network (or stored on a hard drive or memory). Every web page, image, or other type of file is composed of some number of bytes. Large files, such as video clips, may be composed of millions of bytes ("megabytes"). Since website and server performance is heavily affected by the amount of bytes transferred, and web hosting providers often charge according to this measure, it is very important for site owners to be aware of and understand. Common terms incorporating the word "byte" are:

• Kilobytes (K)- one thousand bytes
• Megabyte (M) - one million bytes
• Gigabyte (G)- one billion bytes
• Terabyte (T) - one trillion bytes

Cookie
The cookie file is a file that resides on the client machine. The typical internet user's PC is called a "client". The cookie file contains data passed from web sites, so that web sites can communicate with this file when the same client returns. The web site only has access to the part of the cookie file that represents the interaction with that particular web site; that part of the file is called a "cookie", and a cookie file may contain hundreds of cookies. The cookie file has caused some issues with respect to privacy, because PC users do not know what information is being stored in the file.