Information retrieval is the activity of obtaining information resources. The main objectives of the information retrieval are to supply the right information, to the right user at the right time. Information retrieval mainly deals with the representation, storage, organization and access to information.

Definition of Information Retrieval:

Different author-defined information retrieval differently. Some of them are being:

“Searching and retrieval of information from storage.” (Calvin Mooers)

“Information retrieval is the tracing and recovery of specific information from stored data.” (Oxford English Dictionary)

According to Specification by Subject, “The techniques and process of searching, recovering, and interpreting information from large amounts of stored data.”

Elements or Components of Information Retrieval:

Information Retrieval mainly consists of four elements which are briefly discussed below:

  • Information Carrier: Carrier is something that carries or conveys something. The information carrier is something that carries or store information, i.e. Film, Magnetic tape, CD, DVD, etc.
  • Descriptor: Term or terminology that is used to search for information from storage is known as a descriptor. It can be a name, number, signal, etc.
  • Document address: Every Document must have an author that identifies the location of those documents. Here document address involves with a call number, class number, ISBN, shelf number, accession number, file number etc.
  • Transmission of Information: Transmission of information means to supply any document that is required by the user. Information retrieval system user’s various communication channels to do this. It works like source → transmitter → media → receiver → destination.


Functions of Information Retrieval:

Functions of information retrieval are as follows:

  • Acquisition: Acquisition is the first function of information retrieval. Acquisition means to collect information from various sources. It can be happened through purchase, donation or gift and the resource can be books, documents, journals, etc.
  • Content Analysis: The second step is to analyze the acquired information and figure out its effectiveness.
  • Content Presentation: Information should be presented clearly and effectively so that users can be able to understand them easily. For this purpose (catalogue, bibliography, index, CAS) will help a lot.
  • Creation of Store: In this stage the library authority creates a new file for storing their collected information which is already for presentation, organize, in the same systematic way.
  • Creation of Search Method: The authority will decide what kinds of search logic they may use for searching and retrieving information.
  • Dissemination: The last stage of information retrieval is dissemination. Its an act of spreading information systematically. So the whole function happens like Acquisition → Content analysis Information presentation → Creation of store → Creation of search logic → Dissemination retrieval result → Stop.

Techniques of Information Retrieval:

Two techniques are used to retrieve information effectively which are briefly described in the below:

  1. Traditional System: Traditional system involves the following segments:
    • Catalogue: Catalogue is a list of books one or more library which used as a location tool. It contains author name, title name, edition, number of volumes, place of publication, page number, series name, ISBN, etc. It’s an essential tool for retrieving information.
    • Index: Index is a systematic arrangement of entries designed to enable users to locate information in a certain document. It serves as a crucial information retrieval tool.
    • Abstract: An abstract is a precise and concise reflection of the real document. It serves its users to gain an overall concept about the document without reading it fully. It also serves as a retrieval tool.
    • Bibliography: Bibliography is also a list of books, not confined in a particular collection.
    • Authority File: Sometimes authority applies their own methods to retrieve the information without using existing methods. This method should be written in certain books/file for its further use when the present authority won’t last long.
    • Accession Number: It is also an information retrieval tool that helps to get how to access the information.
  1. Non-traditional System: Non-traditional systems are divided into two main categories which are briefly being:

⇒ Semi-automatic System: It is a combination of human and machine for retrieving information. Besides the use of machines, human intelligence and labour are required by this system. Catalogue card, punch card, EDGE, notes card, apache card etc. are some of the semi-automatic systems.

⇒ Automatic System: This system is being used since 70’s decades. It’s mainly based one computer and networking technologies. The offline network is used in the ’70s but form 80’s to present online system, i.e. real-time sharing is being used. Some of the automatic tools are computer, modem, CD-ROM, hard disk, internet etc. their descriptions are given below:

  • Computer: An electronic machine that can store and work with large amounts of information.
  • CD-ROM: A compact disc used as a read-only optical memory device for a computer system.
  • Hard Disk: A right non-removable magnetic disk with a large data storage capacity.
  • Floppy Disk: A flexible removable magnetic disk (typically encased in a hard-plastic shelf) for storing data.
  • Internet: A global computer network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols.

Today most information is available. The information environment is very complex. Now information is available in the different web-pages. Yet, the reader does not always find the information he/she needs. To find information, a reader uses either a search engine or the reader browses through metadata. The main difference between a search engine and metadata lies int the quality of the links. A search engine offers a lot of results, yet quite a few of the results refer to unusable information. Metadata cover only a small part of the available information, yet the links refer to very useful information. Approximately use of search techniques can help the user to get required information pin-pointedly, exhaustively, timely and economically.