Value of Backlinks ?

Does anyone have any research to indicate how much more valuable a backlink is from each PR value?

I have read the best guess for the exponential factor of PR is 6. And, so in theory that would mean:

1 PR8 backlink = 6 PR7 backlinks
= 36 PR6 backlinks
= 216 PR5 backlinks
= 1296 PR4 backlinks
= 7776 PR3 backlinks
...etc.

Does anyone have an opinion as to whether or not this seems realistic. I have a really hard time believing a single PR7 backlink is going to give me anywhere near the value of 1,000 PR4 backlinks. I have also read another theory that while the PR is exponential, the value of any link has a baseline value and so the exponential factor of the PR system is dampened when calculating backlinks. This seems much more plausible to me but haven't been able to find anything that guesses as to the dampening factor.

All of this is theoretical mumbo-jumbo and I know noone here has the google formula ... but I am trying to determine how many backlinks from theme related sites I need to get to the top in serps for my keywords.

I am using http://www.iblcheck.com/ as a guide and it displays the number of PR4 backlinks. I have access to several PR7 pages to provide backlinks and am just trying to get a feel for how much more powerful backlinks from PR7 sites will be vs. backlinks from PR4 sites assuming everything else about the sites (theme, number of links, etc.) are the same.

I am also really trying to systemitize the SEO I am doing on different URL's so I can try to measure what really is making a difference and what isn't.

Thanks in advance.



In other words, is a PR8 backlink worth 8 times a PR7

Your understanding of PR factors is correct. We can mathematically prove that the factor is between 6 to 7 on average. And the factor is likely larger for higher PR. For sure "PR8 backlink is worth 8 times a PR7", or even more. You can read Google PageRank basics, secrets and common misunderstandings for details.

I think understanding that it is logarithmic in nature is important, but trying to put a scale to it is probably a huge waste of time.

A high PR 7 is way different than a low PR 7. While the toolbar will display some pagerank value, it is not necissarily a current or correct value. Due to the ever changing social structure of the web, endless variables, and extremely rough estimation via the toolbar it would most likely be a huge waste of time to try to calculate some exact value. In addition they could just change the dampening factor a small bit and all your data would be corrupt.

No reason to waste you time trying to figure out the exact mathematics unless you want to learn how to structure large unorganized bodies of data...

I'm not trying to figure out the exact value or exact relationships.

What I am looking for are rough guidelines so I can layout my plan for competing for top serps on my keywords. I know the mantra ... "just keep adding backlinks". I also know there is no way to get to a firm number. I'm wondering/hoping if a rough number is possible if for no other reason than to decide for myself whether or not I can compete for some of my desired keywords.

As a quick example: If I see the top listings for "model car engines" have about 100 backlinks and I see most are PR1-4. Then, is it safe to assume that with a handful of PR6-7 backlinks I might be able to compete?

Can anyone post examples where having just a handful of high PR backlinks has put them above other sites with hundreds of low PR backlinks?

From my understanding the quality (relevence) of the link will soon play an important role in the PR transfered as well.

So a cooking site linking to a gun manufacturer will mean less than a hunting site to a gun manufacturer.

Also there is the matter of the link's text.

having your link say 'google' will be different that if your link text is something like the google bomb 'miserable failure' . So you can gustimate the average of each links worth, but you will not beable to calculate it exactly.

unless you got lots of free time and you enjoy figuring out puzzles...
i find that there are much better uses of ones time than the discovering the intricacies of pagerank exponentialities.