Ranking

Ranking determines the quality of a match between query and candidate document.
Search products consider the following parameters to determine the appropriate rank value

1. Freshness- It determines the age of the document to the point in time the query is issued.
2. Authority- Authority denotes the importance of document as determined by links from other document.
3. Quality- It determines the assigned importance of a document
4. Proximity- Proximity denotes the distance between and location of, query terms in the documents.When a query contains multiple terms that are not detected as known phrases, the ranking process takes the relative position of the terms and determines the most relevant results based on the proximity the matching terms in the document have to each other.
5. Context- Different document fields, for example title, body, description, price, or type, may be assigned different relevance weight. This allows you to specify for example that a match in the title field of a document contribute more to the document's ranking value than a match in the body field of a document.

The releavancy of the document is represented by ranking value.