A ranking is a relationship between a set of items such that, for any two items, the first is either 'ranked higher than', 'ranked lower than' or 'ranked equal to' the second. In mathematics, this is known as a weak order or total preorder of objects. It is not necessarily a total order of objects because two different objects can have the same ranking. The rankings themselves are totally ordered. For example, materials are totally preordered by hardness, while degrees of hardness are totally ordered.

By reducing detailed measures to a sequence of ordinal numbers, rankings make it possible to evaluate complex information according to certain criteria. Thus, for example, an Internet search engine may rank the pages it finds according to an estimation of their relevance, making it possible for the user quickly to select the pages they are likely to want to see.

Analysis of data obtained by ranking commonly requires non-parametric statistics.

Strategies for assigning rankings

It is not always possible to assign rankings uniquely. For example, in a race or competition two (or more) entrants might tie for a place in the ranking. When computing an ordinal measurement, two (or more) of the quantities being ranked might measure equal. In these cases, one of the strategies shown below for assigning the rankings may be adopted.

Ranking of query results is one of the fundamental problems in information retrieval (IR), the scientific/engineering discipline behind search engines. Given a query q and a collection D of documents that match the query, the problem is to rank, that is, sort, the documents in D according to some criterion so that the "best" results appear early in the result list displayed to the user. Classically, ranking criteria are phrased in terms of relevance of documents with respect to an information need expressed in the query.

Ranking is often reduced to the computation of numeric scores on query/document pairs; a baseline score function for this purpose is the cosine similarity between tf–idf vectors representing the query and the document in a vector space model,BM25 scores, or probabilities in a probabilistic IR model. A ranking can then be computed by sorting documents by descending score. An alternative approach is to define a score function on pairs of documents d₁, d₂ that is positive if and only if d₁ is more relevant to the query than d₂ and using this information to sort.

Ranking 1 is an Indonesian game show. In this show, 80 contestants are competed to answering all questions correctly to become 2 strongest contestants to win Rp50.000.000,00 as a grand prize. This show is aired on Trans TV since 5 July 2010 until 8 June 2012, every Monday-Friday at 7.30 - 8.30 AM (UTC+7), and hosted by Ruben Onsu and Sarah Sechan.
On 28 February - 4 March 2011, Sarah Sechan as a host changed by Ruth Sahanaya. On 21–25 March 2011, Cynthia Lamusu changed Sarah Sechan as a host.
On March 27, 2012, Ruben Onsu has chosen as most favourite quiz host in Panasonic Gobel Awards 2012 event.

Regulation