PageRank and Quality Score – How exactly do they work?

What are they for?

Both PageRank and Quality Score are systems that Google uses to rate web pages in order to provide you with the best possible experience when you use their search engine or on an Adwords or Adsense ad.

What is page ranking?

PageRank< ™ > is a system that Google uses to rank web pages.

It is based on the uniquely democratic nature of the web – how everybody else out there votes on your site. As the Google bots work through sites all over the web, they gather information about links; and use this to determine individual page's value. Google uses a link from page A to page B as a vote, by page A, for page B. But, Google looks beyond the sheer volume of votes, or links a page receives. It also looks at the page that casts the vote. If an “important” web page is voting for your page, your ranking improves.

Of course, your pages must also match the query. So, Google uses PageRank together with text-matching to find pages that are both important and relevant to a users’s search. Once upon a time, Search engines would just look at the number of times a keyword appeared on a page – and it was possible to trick them using the keywords hidden away – for example in meta tags. Now Google and the other search engines examine a number of factors on your page - and the pages that link to it- to determine if it's a good match for the entered keywords.

PageRanks are recalculated about once a month and takes about the last third of each month– so don’t expect your web site to start showing up the day you load it up – it will take time.

What is Quality Score?

Google uses PageRank to provide a quality user experience for searchers – so they come back to Google next time they want to search.

Around your search results, you’ll see a lot of advertisements – these are AdWords ads; and are related to the keyword. Google don’t want you to search, click on an that seems to be exactly what you wanted, and only find a site that had little to do with what you were searching for. That’s not a great user experience. So, for similar reasons to PageRank, Quality Score is there to provide a quality user experience for searchers who click on the ads around the search

A key factor in Quality Score is landing page assessment. Google looks to their advertisers to provide robust and relevant content. If they do, their rates are reasonable and have potentially profitable. If not, Google raises the minimum bid required for any keyword linked to that page to between $5 and $20 per click - at which point nobody can make a profit on 99.9% of the products out there.

Quality Score is calculated separately for each keyword. Your score for some keywords may be great and others may be poor for the same ad and landing page.

Some of the other factors are

• relevance,
• the keyword's clickthrough rate (CTR) which Google uses as a mearue of the relevance of the keyword
• your account's historical performance,
• other bids for that keyword – if a it is not highly bid on, you can get a great score even if everything else is lousy – but, in my experience, these are keywords with few click
• Your ad position – or whether your ad is displayed at all - is also influence by what other advertisers are advertising the same product. If somebody else has a better quality, higher bid – Google will display their ad and not yours

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