calculation of pagerank prediction

[adamovic]

Maybe this is not most appropriate forum, but it is search engine programming related forum, so I decided to post this here.brbrI've found the following formula for calculating (predicting) pagerank:brbrdiv style="margin: 5px 20px 20px;" div class="smallfont" style="margin-bottom: 2px;"Quote:/div table border="0" cellpadding="6" cellspacing="0" width="100%" 1px inset ;" rank(x)= 0.15 + 0.85 * The sum of (rank/number of links) br /tbody/table/divbrMinimum rank is 1 (initial).brMaximum is infinity.brI don't know the scale.brThe following should be true :brdiv style="margin: 5px 20px 20px;" div class="smallfont" style="margin-bottom: 2px;"Quote:/div table border="0" cellpadding="6" cellspacing="0" width="100%" 1px inset ;" log rank(x) = approx(google_rank(x)) /tbody/table/divbrAny opinions?

[wasim_at_drushti]

You may use this links to monitor your PR.brhttp://www.iwebtool.com/br

[adamovic]

Originally Posted by wasim_at_drushti

You may use this links to monitor your PR.brhttp://www.iwebtool.com/

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Actually, I have site with 230 backlinks, it seems that there 2 PR7
links and few PR6 and PR5 and each PageRank prediction tool (I tried
few) shows PR0 predicted or cannot determine. br
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I haven't asked for the tool, I asked for the approximation algorithm.br
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[adamovic]

In fact the best tools I've seen so far are at www.seotoolset.combr
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[wasim_at_drushti]

To calculate the PageRank for a page, all of its inbound links are taken into account. These are links from within the site and links from outside the site.brbrspan style="font-weight: bold;"PR(A) = (1-d) + d(PR(t1)/C(t1) + ... + PR(tn)/C(tn))/spanbrbrThat's the equation that calculates a page's PageRank. It's the original one that was published when PageRank was being developed, and it is probable that Google uses a variation of it but they aren't telling us what it is. It doesn't matter though, as this equation is good enough.brbrIn the equation 't1 - tn' are pages linking to page A, 'C' is the number of outbound links that a page has and 'd' is a damping factor, usually set to 0.85.brbrWe can think of it in a simpler way:-brbra page's PageRank = 0.15 + 0.85 * (a "share" of the PageRank of every page that links to it)brbr"share" = the linking page's PageRank divided by the number of outbound links on the page.brbrA page "votes" an amount of PageRank onto each page that it links to. The amount of PageRank that it has to vote with is a little less than its own PageRank value (its own value * 0.85). This value is shared equally between all the pages that it links to.brbrFrom this, we could conclude that a link from a page with PR4 and 5 outbound links is worth more than a link from a page with PR8 and 100 outbound links. The PageRank of a page that links to yours is important but the number of links on that page is also important. The more links there are on a page, the less PageRank value your page will receive from it.brbrIf the PageRank value differences between PR1, PR2,.....PR10 were equal then that conclusion would hold up, but many people believe that the values between PR1 and PR10 (the maximum) are set on a logarithmic scale, and there is very good reason for believing it. Nobody outside Google knows for sure one way or the other, but the chances are high that the scale is logarithmic, or similar. If so, it means that it takes a lot more additional PageRank for a page to move up to the next PageRank level that it did to move up from the previous PageRank level. The result is that it reverses the previous conclusion, so that a link from a PR8 page that has lots of outbound links is worth more than a link from a PR4 page that has only a few outbound links.brbrWhichever scale Google uses, we can be sure of one thing. A link from another site increases our site's PageRank. Just remember to avoid links from link farms.brbrNote that when a page votes its PageRank value to other pages, it's own PageRank is not reduced by the value that it is voting. The page doing the voting doesn't give away its PageRank and end up with nothing. It isn't a transfer of PageRank. It is simply a vote according to the page's PageRank value. It's like a shareholders meeting where each shareholder votes according to the number of shares held, but the shares themselves aren't given away. Even so, pages do lose some PageRank indirectly, as we'll see later.brbrOk so far? Good. Now we'll look at how the calculations are actually done.brbrFor a page's calculation, its existing PageRank (if it has any) is abandoned completely and a fresh calculation is done where the page relies solely on the PageRank "voted" for it by its current inbound links, which may have changed since the last time the page's PageRank was calculated.brbrThe equation shows clearly how a page's PageRank is arrived at. But what isn't immediately obvious is that it can't work if the calculation is done just once. Suppose we have 2 pages, A and B, which link to each other, and neither have any other links of any kind.brbrThis is what happens:- brStep 1: Calculate page A's PageRank from the value of its inbound linksbrbrPage A now has a new PageRank value. The calculation used the value of the inbound link from page B. But page B has an inbound link (from page A) and it's new PageRank value hasn't been worked out yet, so page A's new PageRank value is based on inaccurate data and can't be accurate.brbrStep 2: Calculate page B's PageRank from the value of its inbound linksbrbrPage B now has a new PageRank value, but it can't be accurate because the calculation used the new PageRank value of the inbound link from page A, which is inaccurate.brbrIt's a Catch 22 situation. We can't work out A's PageRank until we know B's PageRank, and we can't work out B's PageRank until we know A's PageRank.brbrNow that both pages have newly calculated PageRank values, can't we just run the calculations again to arrive at accurate values? No. We can run the calculations again using the new values and the results will be more accurate, but we will always be using inaccurate values for the calculations, so the results will always be inaccurate.brbrThe problem is overcome by repeating the calculations many times. Each time produces slightly more accurate values. In fact, total accuracy can never be achieved because the calculations are always based on inaccurate values. 40 to 50 iterations are sufficient to reach a point where any further iterations wouldn't produce enough of a change to the values to matter. This is precisiely what Google does at each update, and it's the reason why the updates take so long.brbrOne thing to bear in mind is that the results we get from the calculations are proportions. The figures must then be set against a scale (known only to Google) to arrive at each page's actual PageRank. Even so, we can use the calculations to channel the PageRank within a site around its pages so that certain pages receive a higher proportion of it than others.brbrNOTE: brYou may come across explanations of PageRank where the same equation is stated but the result of each iteration of the calculation is added to the page's existing PageRank. The new value (result + existing PageRank) is then used when sharing PageRank with other pages. These explanations are wrong for the following reasons:- br1. They quote the same, published equation - but then change itbrbrfromspan style="font-weight: bold;" PR(A) = (1-d) + d(......) to PR(A) = PR(A) + (1-d) + d(......)/spanbrbrIt isn't correct, and it isn't necessary.brbr2. We will be looking at how to organize links so that certain pages end up with a larger proportion of the PageRank than others. Adding to the page's existing PageRank through the iterations produces different proportions than when the equation is used as published. Since the addition is not a part of the published equation, the results are wrong and the proportioning isn't accurate.brbrAccording to the published equation, the page being calculated starts from scratch at each iteration. It relies solely on its inbound links. The 'add to the existing PageRank' idea doesn't do that, so it's results are necessarily wrong.brbr

[adamovic]

Thank you for the huge explanation. Finally I understand the original formula.br
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Originally Posted by wasim_at_drushti

brFrom this, we could conclude that a link
from a page with PR4 and 5 outbound links is worth more than a link
from a page with PR8 and 100 outbound links. br

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Or 10 PR1 links might be same as 1 PR10 link which obviously is not correct.br
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[songchai]

Um, so things to do is only exchange with high PR website, but no one actually accepting such none PR site

[wasim_at_drushti]

that is not the case, you may use some link exchange programs such as link2me.com. Here you can send your request to link to any website as well as recieve the same.brSome sites do have their own link with us pages you may link there. brbr

[angellica2017]

psssst... is Google allowing that?

[wasim_at_drushti]

Yes, There is not issue if you link to any of the site. Google allows this. But there are also some do's & dont's for linking, Like :brbrspan style="font-weight: bold;"Do's :/spanbrConcentrate on related and important links only. Sheer numbers are no longer important. What's important is that the more popular sites on the Web link to your site, as well as making sure that the links pointing to your site are relevant to your topic area. brbr* Make sure that your site is listed in all of the major directories: Yahoo!, the Open Directory Project, and LookSmart. Also, see if your site is relevant to a particular About.com area, and submit it to the guide. brbr* Search for your competitors. Start visiting the sites that are linked to your competitors, and write to see if they'll consider linking to your site. brbr* Create a list of links before you ever contact sites for linking purposes. If the company sees that you've already added their URL to your list of links, they'll be more apt to add your link on their site in return. Again, concentrate on related links only. brbr* Consider what other fields are related to your particular industry and concentrate on getting links from those areas. You won't want to add competing sites to your links' page, but you probably won't mind adding links to sites that aren't direct competitors. For example, if you have a site that sells needlework kits, you won't want to list other sites that sell needlework kits. However, you probably won't mind linking to sites offering related products, such as sewing baskets, books on needlework, or online sewing classes. brbr* When you visit related sites, look to see if they offer guestbooks or forums. If they do, post a message, and include your URL in your signature. brbr* Consider setting up separate theme-oriented domains and link all of your domains together. brbr* Offer a discount of your goods or services for anyone who agrees to post a small graphic on their site that links back to your site. brbr* Create a testimonial page, and write a brief testimonial about any Web site that you'd like to get linked to your site. Inform the site of the testimonial, and encourage them to link to the page. brbr* Or, write testimonials of particular products, and sign the testimonial with your name and URL. Send the testimonials out to the individual companies, and tell them how much you've enjoyed using their products. Many companies will place testimonials in particular areas of their site, and they're delighted to get rave reviews about their products. brbr* Offer awards on your site, and give out little graphics that link back to your site. brbr* Set up an affiliate program, which is an excellent way to boost link popularity. brbrspan style="font-weight: bold;"Don'ts :/spanbrbr* Don't participate in link exchange programs or link farms. Google will ban sites that participate in link exchange programs, and many of the other major engines have also expressed their dislike of artificially created link popularity. brbr* Don't use hidden links on your page. Again, many of the major engines frown on the use of hidden links. brbr* Don't make the mistake of thinking that link popularity isn't important or necessary. A high link popularity is sometimes all it takes to achieve top rankings. It's crucial, in many cases, to the success of an online business. brbr* If you create separate theme focused sites for the purpose of boosting link popularity, don't use redirects on those sites pointing back to your main site. Rather, create a mini site at the new URL with several pages of good, solid content, and then visibly link back to the main site. brbr* Don't bother with free-for-all pages. Generally the only thing these pages will guarantee is an increase in email spam if you participate. brbrbrbrbr