Google’s system for ranking web pages is called PageRank. It is commonly referred to as PR. PageRank actually represents a range of values on a scale of 0 to 10.  You can see the PR of any web page if you download the Google Toolbar for your web browser and enable the PageRank slider on the toolbar. The higher the PR number, the greater the PageRank value. 

At The Digital MultiMedia Store, based in Vancouver, we extensively research Google's continuously evolving algorithms to ensure that we take the proper action to optimize web sites for our clients.  

In essence, the major variables in determining PR performance of any web page are: the number of inbound links, the number of outbound links and the number of internal links between web pages on the site. The number of web pages on a web site is also very important. 

Google published PageRank formula:

PR(A) = (1-d) + d(PR(t1)/C(t1) + ... + PR(tn)/C(tn))
 
't1 - tn' are pages linking to page A
'C' is the number of outbound links that a page has
'd' is a damping factor, usually set to 0.85

a page's PageRank = 0.15 + 0.85 * (a "share" of the PageRank of every page that links to it)
 
"share" = the linking page's PageRank divided by the number of outbound links on the page.

The value for a web page is 85% of the PR, divided by the total number of outbound links. Therefore, the more links there are on a web page that provides an inbound link to one your web pages, the less PageRank value your page will get from that inbound link. A link from a PR8 page with lots of outbound links is better than a link from a PR4 page that has few outbound links.

The mathematical relationship between the values of the different PR levels is logarithmic (estimated base 5.5). PR5 is worth 4 to 6 times more than a PR4.

If you want to increase PR, add links from pages with higher PR.  

The maximum PageRank for a web site equals the number of pages on the site multiplied by 1. This maximum amount of PageRank is distributed between the pages on the web site by internal links. The maximum PR is increased by inbound links from other sites and decreased by outbound links to other web sites.

The maximum amount of PageRank for a web site increases as the number of pages on the site increases. The more pages that a site has, the more PageRank it has.

The only way to increase the maximum PageRank for a web site is to add more inbound links and increase the number of pages on the site.

Outbound links have a negative impact on a site's total PR. To counter this effect, outbound links should be reciprocated.  Reciprocal links can gain or lose PR based on the PR of the pages linked to and the number of outbound links on those pages.

Outbound links from a web page negatively impacts all of the web pages in the internal link structure of your site. The page that has the outbound links looses the most PR. So it is best to place outbound links on those web pages with the lowest PageRank. Other action can be taken to counter PR loss such as include coding on the web page that prevents Google's web site crawler, called GoogleBot, from recognizing and following the outbound link from the web page.

If you have any questions about Google PageRank or any other topics related to search engine optimization, please feel free to contact us by sending an e-mail.