## The Spreadsheet - a simple structure

Consider the simple set-up to the left. This structure is already typed into the spreadsheet.

Page1 links to Page2, 3, 4 and 5 - and they all link back to Page1. The set-up is entered like shown below:

How to specify the simple structure |

The first iteration |

Page1 has 4 other pages linking to it - so it gets a high PageRank in the first iteration.

Each of the pages 2, 3, 4 and 5 has only one inbound link, namely Page1. So each of them get only a quarter of Page1's initial PageRank - plus a little damping (see the description of the the formula).

Notice that the sum of the Page Ranks is 5 - so the average is 1.

The second iteration |

The values converge |

**lower**PageRank because the four pages that link to it had a low PageRank in the last iteration. The four pages get a

**higher**PageRank because they are linked to from Page1, which had a high PageRank in the previous iteration.

The results are oscillating - but if you make more iterations, you'll see that the results get closer and closer to a final value - as shown at the right.

Try altering the spreadsheet by making more internal links or adding more pages - and see how the PageRank distributes.

The simple structure concentrates PageRank on the home page more than any other structure does. Page1 has a PageRank that is almost half the site's total PageRank. For each new page that is added to the site, Page1's PageRank will grow by a value close to 0.5(1) whereas the PageRank of the existing sub-pages will drop slightly, because Page1 now must feed more sub-pages.

Next: The pyramid structure.