*3.1.4 Several relevant facts about webometrics ranking of universities*

Results of ranking of universities [58] have been published two times a year since 2004 (data are collected during the first week of January and July to be prepared and published in the end of both of the months) covering more than 28,000 institutions of higher education all over the world with their analyses.

The data are collected between January 1 and January 20, depending on a current edition of a ranking publication. Data are taken (sampled) for each of the variables at least two times during the certain period, and the greatest value is taken as the final value to be analyzed in order to avoid possible errors in data collection. Inconsistency of web search engines is very huge so that the obtained results may be diversified, and there is a small possibility for their replication if browsing is done several days later. Google is very geographically biased; that is why data are collected with *google.com* mirror related to the domain, and English is used for the interface and Madrid (Spain) as the location.

A final publishing of ranking data is performed at the end of January or July, usually not before the 28th day of the month. It is very important to mention that Cybermetrics Lab follows its general rule not to discuss any presented result or provide unprocessed data with which a specific ranking was performed [58].
