SDI (Selective Dissemination Information) | Element & Steps of SDI


Luhn defined SDI (Selective Dissemination Information) as SDI is a machine-assisted service provided by any organization that receives and delivers the latest information where it is needed.

All types of topical awareness services are operated manually. After the advent of the computer in 1950 AD, efforts were made for its application to library and information works. Hans Peter Luhn proposed a computer usage method for topical awareness service in 1961, he named the method of automated topical awareness service, selected information broadcasting or SDI.

The set of each piece of information is selected for transmission to the user related to the computer. Hence this service is called Selected Information Broadcasting.

Selective Dissemination Information (SDI) Service is aimed at an individual or a small group, yet attempts are made to make SDI broadcasts as needed by an individual or a small group.

Thus, the user gets only the information he wants or selects. In this way, the user gets only such information. Which is useful for him.


Selective Dissemination Information
SDI - Selective Dissemination Information

Element of SDI (Selective Dissemination Information)


SDI system can have the following components or elements

1. A Document Database - This is a file containing the description of the document and the words representing the subject matter. Since SDI is a computer-based service, the database of the document is readable on a computer. The database in SDI is for timely literature.

2. Set of user-profiles - This is a file that describes the subject of the user's interest. The user file is also a computer-readable file. Creating user profiles is an important task. User-friendly words are taken from the same vocabulary list used to index the contents of the document data.

3. Matching Profiles - This involves the computer mixing the documentation with the user details. This is actually done by the program working inside the computer.

4. User Interface - Interface is a common limitation that allows for useful communication. The interface is the main function in the SDI (Selective Dissemination Information) service.

Steps of Selective Dissemination Information 


There are four stages of SDI which are as follows:

(1) Selection The subject of selection activities or new documents is matched in favor of topics and features of user interest.

In the selection side of SDI, the computer program within the database matches the keywords of the new document according to the subject of interest of the user.

In the selection side, documents are selected to broadcast only those documents that satisfy the user profile (search expression) given the user's interest.

(2) Notification - After selection, the selected material has to be notified for broadcast. Normally, notifications are in the form of abstract or abstract reference lists as the SDI service is for new notifications.

Therefore, it is important that adequate information is given about the documentation in this service. 

Emphasis is placed on the authoritative description of all documents included in the SDI service. Selected documents are notified with computer program documentation matching.

(3) Feed Back: - The notification has two parts-
  • User parts
  • Reinvestment portion

Some questions in the reinvestment section are about the usefulness of documents. The user is asked to reply to the notification, that is, the user receives the information related to the document related to his interest, in view of their usefulness and need for themselves, and reacts to that document. Many times, the user's subject interest also changes

In this way, sends its response to the library and information specialist. The expert analyzes these reinvestments. And improves user profiles on the same basis.

(4) Modification - After receiving notification there is a meaningful interaction between the "SDI system and usage"

When the user of his reinvestment reveals that his requirements have not been met, then the information expert will modify the user profile. 

Sometimes. Starting with new projects also changes the user's interests. The changing interests are adjusted in his / her profile. Thus the user profile is modified regularly.

(5) Resolution of the will of the readers - If a particular reader demands an original copy of a document, it is provided to him. 



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