Ranking

A hierarchy (also ranking, ranking, ranking [ ræŋkɪŋ ] ) is a sequence of several similar objects whose order determines a rating. Popular examples are world rankings in sports and music charts. The one-dimensional arrangement of a hierarchy simplifies the comparison and make a selection: so are sorted when the search engine ranking results of a search query according to their relevance. Rankings can search for simple, even controversial, criteria are created or as a result of elaborate comparative studies. Frequently their sequences form from the ingredients of hierarchies. A specific position in a hierarchy is also referred to as placement.

Examples

• The pecking order is most often used in behavioral biology equivalent rank, when it comes to describe the hierarchy in groups of animals. The word pecking order goes back to the Norwegian zoologist and ethologist Leif Thor Schjelderup - Ebbe, according to the studies introduced this term to the dominance behavior of chickens.
• The place in protocol order of the individual states assigns the holders of public office corresponding to their nominal significance. At the top is usually the head of state, followed by the highest representatives of the three branches of government.
• In university rankings, the quality of research and teaching are valued at universities and usually published in the form of sorted by subject rankings in magazines. In Germany is known, for example, the university ranking produced annually by the Centre for Higher Education Development.
• In magazine reviews the quality of scientific journals will be evaluated.
• The search engine ranking results of a search engine in information retrieval is important. In order to achieve the highest possible position, various methods of search engine optimization have been developed.
• Cities and nations rankings are created by numerous organizations to compare cities or countries according to certain criteria together. Examples include the Corruption Perception Index of Transparency International, and the created by the Bertelsmann Foundation ranking of German locations.
• Charts place due to certain collection methods for a specified period of time is also a ranking according to certain criteria ( single, LP or pop music, soul, etc.) firmly.

Other examples are:

• The Social Status in sociology
• Grade of service in the military
• The rank classification of warships
• The ranking of the rankings in a competition
• The art compass in the visual arts

Statistical analysis of rankings

The investigation of the rankings with the help of statistics ( rank order statistics, for example, using the Wilcoxon rank sum test ) provides in many cases significant advantages over the analysis of the raw data by the t-test, because rank tests are significantly more resistant to extreme values ​​and nonlinearities. The formation of the ranks under investigation units are brought into a ordinal scale; the sums of the absolute differences between adjacent values ​​then act less strongly on the test result from, which increases especially in mehrgipfeligen distributions of the raw data, the detection capabilities of significances.

Rankings are usually based on several criteria, which are offset to a total value. This leads to the fundamental problem that the transfer method can significantly affect the results.