The Number of Backlinks and its Relationship to PageRank

 Search engine optimisation or SEO is the science of making the most of a website in terms of attracting new visitors and potential clients,

SEO may be divided into on-page optimisation and off-page optimisation. On-page optimisation relates to content within the website and webpages. Off-page optimisation depends on increasing total value of backlinks to your website and web page.

Off-page factors are more important than on-page factors in terms of top positioning on search engine results pages. It is thought that off-page factors may account for up to 80% of the Google algorithm.

 I thought we needed to define the relationship between PageRank and the number of backlinks to a page and I therefore undertook an analysis of 500 HomePages. These were obtained on Google for several different countries such as Google.com  the United States. Google.co.uk - the United Kingdom and Google.com.au - Australia. I looked at  search engine results pages for short- and long-tail keywords.

You can determine the number of links for a page on a search engine of your choice by typing into the search box link:www.yourURL.com  for the HomePage of the full URL for an internal page  eg. link:www.yourURL.com/page.html. I chose AllTheWeb as my preferred search engine.

You can see that for this website 'Keyword SEO Pro' AllTheWeb knows of 5140 links. For this figure I used Link Popularity Check, a free program provided by Xandra who produce Internet Business Promoter. You can see the different number of links on the different search engines. This is for my website www.2womenshealth.com. AllTheWeb has 5800, Alta Vista 6,000, Google just 16 and Yahoo 4900. Google always tends to report very few links and I gather this may be because they only report links from high PageRank pages, probably PageRank 4 and above.

This table indicates the data obtained from the study. The column on the left indicates PageRank from 1- 9. The second column, the number of pages analysed for each PageRank, the third column the average number of links for each PageRank and the final column the range.

Not surprisingly the average number of backlinks for each PageRank gradually rises as PageRank rises from an average of 77 for PageRank 1 through to more than 10 million for PageRank 9. With a link gathering campaign, it should be possible to achieve PageRank 3 which requires an average of 615 links and even PageRank 4 is more than 2,500, but a PageRank 5 would require 70,000 and gathering links by a link building campaign would be unlikely to achieve such a PageRank.

 This data demonstrates two interesting phenomena. Firstly, there is a very large range for each PageRank of the number of backlinks required. For instance, for PageRank 5 I found one page with just 88 is backlinks and, at the other extreme, nearly 6,000,000.

The second interesting observation is that there is an overlap between the ranges for the different PageRanks. We must now address the question as to why there should be such a large range of backlink requirements for the different PageRanks and also why there is an overlap. We must remember that not all backlinks are of equal value. Value of backlinks varies enormously.

Firstly, the value depends on the PageRank of the linking page. All things being equal, a link from a page of PageRank 6, will carry six times the value of a link from a page with PageRank 1. Links from pages with PageRank 0 carry no value.

The value of the link also depends on the number of links on the linking page. All things being equal, if one page has just two links and another page has 20 links then the value of the link from the one with just two links would be ten fold the value of the link on the page with 20 outbound links.

We also believe that the value of a backlink is modified by the relevance of the linking page and also by the anchor text.

Google provides us with just integer information on PageRank but we know that Google uses several decimal points. Thus, we could have a PageRank of 3 but Google knows that the PageRank 3.999 and virtually 4.

Finally, we must remember that the PageRank information available to us is always at least three months out of date.

PageRank is an overview of the four factors above. PageRank is superior just to backlink numbers and PageRank is the best available modality available to us for evaluating off-page optimisation. This study, together with the discussion of the results has recently been published - June 2010 on ezinearticles.com.