‘Update’ refers to the process of search results renewal. When the results are updated, some sites may make it to the top 10, some other sites may "sink". Every search engine has its own update style which becomes clear in this analyzer. Every day the search engine update analyzer monitors the top ten responses to 140 queries in order to assess the number of sites that changed their positions, and how much the positions have changed.

Let Di be the change in position for the page that appeared i-th in top 10 search results on day 1. For example, if the fifth page from the first day top 10 appeared third or seventh on the second day, D5=2. If the second day top 10 did not contain a certain page which was present on the first day, then we will assume that Di=10 for that page.

The update indicator is calculated using the formula:

10
∑ Di/100
i=1

Consider a couple of examples:
Example 1
On Day 1, a certain query has the following Top 10:
C1, C2, C3, C4, C5, C6, C7, C8, C9, C10.
On Day 2, the same query has this Top 10:
Cn, C1, C2, C3, C4, C5, C6, C7, C8, C9.

In this case the update indicator is calculated as follows:
((2-1)+(3-2)+(4-3)+(10-9)+10)/100 = 0.19 (19%)

Example 2
For Day 1, a certain query has the following Top 10:
C1, C2, C3, C4, C5, C6, C7, C8, C9, C10.
For Day 2, the same query has this Top 10:
Cn1, Cn2, Cn3, Cn4, Cn5, Cn6, Cn7, Cn8, Cn9, Cn10.

In this case the update indicator equals:
10*10/100 = 1.00 (100%)

The analyzer also calculates the additional parameters: the number of sites which disappeared from the search results and the number of sites which changed their positions.

This analyzer has no valuation. The results can be interpreted in two ways: a search engine that has frequent large updates could be considered more up-to-date; a search engine with rare updates can be considered more stable and predictable. The informer of this analyzer sorts the search engines in the ascending order of update level.