Explanations on PageRank algorithm
Posted by Marielle Chapuis | in Uncategorized | on 15-07-2010
Hi everybody,
PageRank or PR is a grade between 0 and 10 that applies to a website according to its popularity. Each link to a page represents a vote. If page A links to page B, it gives a vote to it which means that page B deserves to be visited. The more a website has relevant incoming links, the greater its PageRank.
Description of PageRank algorithm
PageRank on page B calculates as follows:
PR(B) = (1-d) + d (PR(A1) / N(A1) + … + PR(An) / N(An) )
- PR(B) : PageRank of page B
- PR(An): PageRank of page A
- N(An) : number of links on page A
- d : all the votes are added up and the total is multiplied by the attenuation coefficient d= 0.85
- (1-d) : this formula assures that the PageRank average for all the pages of a website equals 1
PageRank takes into account two factors: the PageRank of the page that is hosting your link and the number of outbound links on that same page. It is better to place a link on a page having few links and a high PageRank.
Through PageRank, Google measures the probability of an Internet user to visit your website. A probability is a figure between 0 and 1. A page with a probability of 0.75 would mean that an Internet user has 3 in 4 chances to visit your website.
Imagine a results page after a search displaying only 5 results. The probability for visiting these pages is 0.20. But this example is utopian because in reality it is very different since Google indexes hundreds of billions of pages.
Maintain a good PageRank
In order to keep a good PageRank, it is important to regularly improve its link building since the greater the number of pages indexed by Google, the more risky it is to be less well classified. As PR is based on a logarithmic scale, having a link from a site with a PageRank of 4 is twice better than a link with a PR of 2.
However, don’t think PageRank alone will bring you good positioning. 200 other factors are taken into consideration for Google SEO. If you want to know more about that, I suggest you to read the article: PageRank is useless!
