CODEWITHSUNDEEP
search-enginemarkov-chainspagerank
bilanush
bilanush

Reputation: 139

What do 'random jumps' in Google's pageRank really mean?

I read somewhere that the added S matrix of 1/n elements together with the fudge factor 0.15 which Google uses is just not accurate and just comes to solve another problem.

On the other hand I have read somewhere else that it does have a meaning. And it is used for random jumps. We first ask whether a surfer wants to continue to click or not. So according to what I read the meaning is -85% continue to click -15% don't.

My question is... this is maybe good for first click. But how does this work in other iterations? How can anyone land at a random page? Isn't it the whole assumption of page rank that every one is linked to the other?

If I can just land on a page without coming from somewhere else then the ranking isn't accurate at all.

But most importantly I don't understand what does the added 1/n matrix mean? If I am at a page I can only click on clicks which I see. What does it mean to say that I can go somewhere else?

If they mean that I just Google search again then why don't call it a second chain? Why include it in the first ?

Also, is it 15% that I randomly jump or 15% that I stop surfing? (Or are they the same thing? )

And to my first question - is it a fudge inaccurate factor that is made to solve other problems or it does really mean something as said above and it IS a correct measurement to include it even by its own merit?

Upvotes: 0

Views: 729

Answers (1)

Curtis Fenner
Curtis Fenner

Reputation: 1412

"Random jumps" could correspond to lots of things:

  • Entering an address in URL bar
  • Visiting a "Favorite" link
  • Visiting a home page (or any one of the links on it!)
  • Visiting a link from a content aggregator / social media

People do actually do these things when browsing online; going to a random page in your index is a very crude approximation of this behavior.

If you're Google or some other entity with lots of surfing/tracking data, you can actually measure the probabilities people "jump into" particular websites to get a better model! The random-jump probabilities don't need to be totally uniform; they just need to be non-zero for every website.

The random-jumps is the simplest way to ensure the matrix/corresponding chain is Ergodic which makes it easier to analyze and guarantees convergence.

Upvotes: 1

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