PageRank definition and relation to SEO
PageRank is Google’s assessment of the importance (authority | reputation) of a web page based on incoming link values.
- The PageRank of the HomePage of a website is the best means available to us of Domain Authority as seen by Google.
- The PageRank (PR) of the webpage we are browsing appears in an indicator on the Google toolbar (Internet Explorer or Firefox only). We are only shown integer values of PageRank and not the decimal places known to Google (PR 4 rather than 4.6788834 for example).
- The team at Google is remarkably adept at revealing a little information whilst concealing many key facts.
How does Google determine PageRank?
Google determines PageRank of a webpage in two stages.
- Each link recognised by Google to a webpage is given a value according to the PageRank of the page giving the link and this is divided by the number of outgoing links on that page. The value of all the incoming links to that page is then summated.
- All webpages indexed by Google are placed in a table such that those with the most incoming ‘link juice’ are at the top – PageRank 10. We see webpage PageRank as integers 0-10 although Google knows the decimal
places. PageRank is on a logarithmic scale and SEOmoz suggest that it has a base between 8 and 9 rather than the more conventional base 10. If it is 8 this would mean that for every webpage with PR10 there would be 64 with PR 8, and 858,993,452 pages with PR0.
The webpages are not in 11 groups (PR0 -10) but in a continuous league because of the decimal places known to Google.
- Google may adjust the value of a link in its index. For example, links in footers on every page may carry less weight than a link in the body text.
- There are many databases of links including MOZ (previously SEOMoz), BacklinkWatch, AHRefs, SEOSpyGlass. Google only uses the links in its database but provides no public access to it. Links in non-Google databases are a poor reflection of those in the Google database.
PageRank was initially of importance as it related to individual pages but there have been important changes. Google tells us “When Google was founded, one key innovation was PageRank, a technology that determined the “importance” of a webpage by looking at what other pages link to it, as well as other data. Today we use more than 200 signals, including PageRank, to order websites, and we update these algorithms on a weekly basis.” It is apparent that PageRank relates now to websites and not only to webpages. The most obvious indicator of website PageRank is the PageRank of the website’s HomePage.
The majority of web professionals have come to disregard PageRank as having meaning in search engine optimisation mainly because there are many webpages with PageRank 0 on Google’s top results pages for highly competitive keywords. This appropriately leads to the conclusion that the PageRank of a webpage cannot be the top factor in the Google algorithm. However, I have previously indicated that the majority of top positioned webpages with PR0 are either on websites with HomePage PageRank of 4 or more or these webpages are themselves the HomePage of the website.
PageRank is Google’s Indication of Page Authority and Domain Authority
HomePage PageRank is one of the top positioning factors in the Google algorithm (Viniker 2011).
Modern search engines rank webpages by relevance and reputation (importance, authority or popularity).
The reputation depends on domain authority and page authority. (Dover D 2011).
Web Page Authority – Total Page Reputation
The total authority of a webpage is called the Total Page Reputation.
The Total Page Reputation of a webpage TPR = PR + HPR*
PR – PageRank of the webpage | HPR Page Rank of website HomePage | * the effective HomePage PageRank is boosted to a minimum of 4.5 when the website’s HomePage is competing for a keyword.
Keyword Difficulty – Feasibility of Achieving First Page on Google.
If you target keywords that are too difficult for your webpages to achieve top page positioning on Google, you will waste time, effort and money.
The following video explains keyword difficulty in more detail.
Positioning on Google
Positioning on Google (we are aiming for the first page) depends on Relevance and Reputation.
Relevance. “As Larry Page said long ago, we want to give you back “exactly what you want.” Relevance is determined by the use of keywords and synonyms on the page and in the underlying coding.
When Google was founded, one key innovation was PageRank, a technology that determined the “importance” of a webpage by
looking at what other pages link to it, as well as other data. Today we use more than 200 signals, including PageRank, to order websites, and we update these algorithms on a weekly basis.” –
http://www.google.com/about/corporate/company/tech.htmlIt is helpful to consider each link as carrying ‘link juice’. One link authority unit is the value of a link from a page with PR1 and with one outgoing link. In this figure, Matt Cutts showed us that if one page has 100 units of link juice and 2 outbound links, then those two outbound links have 50 units of link juice. The lower page has 9 units of incoming link juice and three outbound links; each of the three outgoing links from this page has 3 units of link juice. Matt tells us that “this is the literally the idea behind PageRank. It’s that simple.” PageRank is Google’s evaluation of Domain Authority and Webpage AuthorityYou can see the PageRank of the page you are viewing with Internet Explorer or Firefox browsers with the Google toolbar installed. Google recognises authority of a webpage by the incoming links from other
- Invariably, every page on a website has a link to the HomePage.
- Incoming links to internal webpages will result in some link juice going to the website’s HomePage.
- The HomePage of a website usually has the highest PageRank of all the pages on the website.
- The value of each incoming link depends on the authority of the linking page divided by the number of outgoing links on it.
- The PageRank of the HomePage of the website indicates the importance (domain authority) of the website.
- PageRank is on a scale of 0-10 with top pages such as Google having PageRank 10.
- The PageRank scale is logarithmic.
Examples of PR10 websites – usa.gov; facebook.comPR9 bbc.co.uk; nytimes.com/PR8 cnn.comMajor national media websites tend to have PRs 7-9.There are many directory websites.
- Examples are directories of professions and directories for localities. These typically have PRs 4-7.
There is evidence that Home Pages that are competing for a keyword receive a boost in their effective PageRank to a minimum of 4.5
10 Hidden Key Facts You Need To Know About Getting To The Top Of Google
- HomePage PageRank (HPR) is the top factor in the Google algorithm:
Compelling and readily verifiable evidence has recently been published that demonstrates this (G-Factor-1). A pop-up appears by the indicator when we hover the cursor over it informing us that “PageRank is Google’s view of the importance of this page” followed by a number/10. The author believes that we should read this more fully as – “PageRank of the HomePage is Google’s view of the importance of this page – number/10″.
- Google gives a boost to the effective PageRank of a HomePage that is competing for a keyword; this is the second factor in the Google algorithm (G-Factor-2).
- We are only shown integer values of PageRank and not the decimal places known to Google (PR 4 rather than 4.6788834 for example)
- As PageRank has many decimal places, changes to PageRank as far as Google is concerned, are usually no more than a small upward or downward slide along a continuous curve. If a webpage has an HPR of 6.00001 we will see it as PR6. Even if the total value of incoming links to the page stays constant, the Google index of webpages is expanding and this page may slip to a PR of 5.99999 but we will see it as PR5 at the next PageRank update. In terms of positioning on the SERPs, there would be no change because, from Google’s perspective, there has been virtually no change in PR.
- Google frequently updates PR information for itself but only releases updates to the public at intervals varying between a few weeks to many months.
- When PageRank updates are released, they are already out of date by at least three months.
- Google tells us that ‘Page’ in PageRank relates to one of the two Google co-founders – Larry Page. Whilst this is undoubtedly true, it also refers to the webpage.
- If all the other factors (there are at least 200) of two webpages competing for a keyword are identical, the one with the higher HPR would be listed above the other in Google’s search engine results pages (SERPs).
- Google does not keep us fully informed about those links to a website that it recognises. A ‘link:URL’ search on Google will return only a few of those revealed by other search engines.
- The best indicator of keyword difficulty is the average Total Page Reputation of the webpages on the top Google search engine results page (SERP) – TPR. These tend to be in a narrow range.
PageRank is Logarithmic
Experts are divided as to the base number of the log scale but one group (SEOMoz) with good quality data, suggest that it is to a base somewhere between 8 and 9. If it is 8 this would mean that for every webpage with PR10 there would be 8 with PR9, 64 with PR 8, 512 with PR7 and 858,993,452 pages with PR0.
The results of a pulished study shows the relationship between the number of backlinks and PageRank for 500 HomePages.
The Relationship Between PageRank and Backlinks – EzineArticles.com
Google moved ahead of its search engine competitors by incorporating user signals into its positioning algorithm. Initially this focused on PageRank but the recent Panda updates take into account additional signals such as time spent on a website. Reassuringly, published keyword difficulty data analyses before and after Panda have demonstrated that the average HPR-KD
for a cohort of 1000 keywords has remained stable. Those webpages that were demoted by Panda have been replaced by others with similar HPR.
The majority of respected search engine optimizers have come to the opinion that PageRank has lost most of its earlier importance and many regard PageRank these days as irrelevant. It is impossible, retrospectively, to evaluate the importance of PageRank when it was first introduced into the Google algorithm more than a decade ago. The literature, however, would
suggest that the PageRank of the individual page played a major role in determining positioning on SERPs at that time.
There are many examples of internal web pages with PR0 having top page positioning on Google for extremely competitive keywords. Clearly, PageRank of internal pages is not currently a major factor in the Google algorithm.
It is this observation that has led so many SEO experts to give little import to PageRank in webpage positioning.
Domain Authority and HomePage PageRank
Search engine optimisers are agreed that incoming links to webpages are even more important than webpage content in determining webpage positioning on the search engines such as Google.
It is apparent to anyone regularly conducting searches on the internet that some websites, such as Wikipedia, often appear on the top search engine results pages. Such domains are said to carry authority that lifts them up
the positioning algorithms. It is a matter of conjecture as to how Domain Authority is best defined.
SEOmoz’s Domain Authority represents their expert’s best prediction about how a website will perform in search engine rankings. They recommend using SEOmoz Domain Authority when comparing one site to another or tracking the “strength” of a website over time. SEOmoz’s Domain Authority is calculated by combining all their other link metrics (linking root domains, number of total links, MozRank, mozTrust etc.) into a single score. The SEOmoz’s Domain Authority involves a complex derived formula the details of which are not made publically available.
50,000 Top Webpages Study = UK USA Canada Australia and India
The PageRank of the top pages on Google (UK, USA, Australia, Canada and India) for 1000 keywords (approximately 50,000 webpages) on:-
are presented on ‘5 Countries 1000 KWs 50,000 webpages‘
94% of the top 50,000 webpages are either
- On websites with HomePage PageRank of 4 or more. (G-Factor-1)
- They are HomePages. (G-Factor-2)
You can check the PageRank of the top Google results pages and the corresponding HomePage PageRanks manually.
KeywordSEOPro will do this on automatic pilot for you. It is the best keyword difficulty tool available.
PageRank – Importance for SMEs in
Dover D. Search Engine Optimization Secrets. Wiley. Indianapolis 2011 page 8.
Viniker DA. The Top Two Factors In The Google Algorithm: A Clinical Approach. EzineArticles 2011
Viniker D. The Relationship between PageRank and Backlinks EzineArticles 2010