Objectives of the Webometrics Ranking of World's Universities
The original aim of the Ranking was to promote Web publication. Supporting Open Access initiatives, electronic access to scientific publications and to other academic material are our primary targets. However web indicators are very useful for ranking purposes too as they are not based on number of visits or page design but on the global performance and visibility of the universities.
As other rankings focused only on a few relevant aspects, specially research results, web indicators based ranking reflects better the whole picture, as many other activities of professors and researchers are showed by their web presence.
The Web covers not only only formal (e-journals, repositories) but also informal scholarly communication. Web publication is cheaper, maintaining the high standards of quality of peer review processes. It could also reach much larger potential audiences, offering access to scientific knowledge to researchers and institutions located in developing countries and also to third parties (economic, industrial, political or cultural stakeholders) in their own community.
The Webometrics ranking has a larger coverage than other similar rankings (see table below). The ranking is not only focused on research results but also in other indicators which may reflect better the global quality of the scholar and research institutions worldwide.
We intend to motivate both institutions and scholars to have a web presence that reflect accurately their activities. If the web performance of an institution is below the expected position according to their academic excellence, university authorities should reconsider their web policy, promoting substantial increases of the volume and quality of their electronic publications.
Candidate students should use additional criteria if they are trying to choose university. webometrics Ranking correlates well with quality of education provided and academic prestige, but other non-academic variables need to be taken into account.
Comparison of the main World Universities' Rankings
Coverage of the Webometrics Ranking of World Universities
This table summarize the actual coverage of the Ranking, in terms of number of countries and higher education institutions around the world.
Design and Weighting of Indicators
The unit for analysis is the institutional domain, so only universities and research centres with an independent web domain are considered. If an institution has more than one main domain, two or more entries are used with the different addresses.
The first Web indicator, Web Impact Factor (WIF), was based on link analysis that combines the number of external inlinks and the number of pages of the website, a ratio of 1:1 between visibility and size. This ratio is used for the ranking, adding two new indicators to the size component: Number of documents, measured from the number of rich files in a web domain, and number of publications being collected by Google Scholar database.
Four indicators were obtained from the quantitative results provided by the main search engines as follows:
Size (S). Number of pages recovered from four engines: Google, Yahoo, and Bing Search.
Visibility (V). The total number of unique external links received (inlinks) by a site, according to Yahoo Site Explorer.
Rich Files (R). After evaluation of their relevance to academic and publication activities and considering the volume of the different file formats, the following were selected: Adobe Acrobat (.pdf), Adobe PostScript (.ps), Microsoft Word (.doc) and Microsoft Powerpoint (.ppt). These data were extracted using Google, Yahoo and Bing.
Scholar (Sc). The data is a combination of items published between 2006 and 2010 included in Google Scholar and the global output (2004.-2008) obteined from Scimago SIR.
The four ranks were combined according to a formula where each one has a different weight but maintaining the ratio 1:1:
The inclusion of the total number of pages is based on the recognition of a new global market for academic information, so the web is the adequate platform for the internationalization of the institutions. A strong and detailed web presence providing exact descriptions of the structure and activities of the university can attract new students and scholars worldwide.
The number of external inlinks received by a domain is a measure that represents visibility and impact of the published material, and although there is a great diversity of motivations for linking, a significant fraction works in a similar way as bibliographic citation.
The success of self-archiving and other repositories related initiatives can be roughly represented from rich file and Scholar data. The huge numbers involved with the pdf and doc formats means that not only administrative reports and bureaucratic forms are involved. PostScript and Powerpoint files are clearly related to academic activities.
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