Selective Dissemination of Information (SDI) Service

1. Introduction: Selective Dissemination of Information (SDI) Service is a refinement of CAS service which is directed to individual / personal requirement (personalized). It provides a deeper analysis of literature. If two people exactly match in terms of their interest, then SDI also can be provided to the two people. Hans Peter Luhn of IBM is a pioneer in this field.


2. Need: The aim of SDI is to see that the user should neither be provided too much of information nor made to miss information essential for his requirements. It should also meet the user need at individual level.

3. Steps in SDI: The steps in providing SDI services are same as that of CAS, the difference is only in the depth of the interest. So, the steps involved in SDI may be of the following types

a) Creation of User Profile: The profiles of the user, who are to be given CAS service, are prepared. A profile may consist of the following fields and can be noted down in a database or Microsoft Excel sheet.

i) Name

ii) Designation

iii) Subject

iv) Keywords that collectively characterize the subject interest of an individual.

v) Email Id

vi) Mobile Number

vii) Fax

viii) Complete postal address, etc

            The first four fields will identify the person and the last four fields will be used to deliver the CAS to the user. The profile can be of a single user or a group working on the same project or some limited subject field. The profile obtained thus must be kept up-to-date. Therefore, if the topic of inertest changes then the corresponding profile must also be modified accordingly. In some organizations, the interest profile was much more than a simple list of keywords. Librarians or information professionals conducted extensive interviews with their clients to establish a fairly complex profile for each individual.

b) Acquisition of Resources: The different sources of information, periodicals, research papers, which are relevant to the parent body, must be selected and collected from different sources. In the next step, through rapid reading the resources are scanned by the LIS professionals to find out the key concepts.

c) Creation of Document Profile:  The relevant and significant information is recorded in the form of content list for different contexts. The recorded information may be in the form of an abstract or an extract. Depending upon the significance of the document, the bibliographical details and indexing terms and the information itself are stored on the file / magnetic tape / computer document.

d) Matching Profile: In a regular interval, the user profile should be correlated or matched with the document profile. The computer compares the two inputs; the output is printed out in the form of two cards. One card is called information card that contain either the list of document or the information itself along with bibliographical details of document which also has a tear off strip request note. The other card is called response card.

e) Notification / Information Communication: If there exists any matching between the two profiles then the matching information is sent to the user or group of users, who may require it, through different means of communication in anticipation, like telephone calls, postal mail / email / SMS with a request to call at the reference desk to get the pertinent information. In case of postal communication, the two cards are sent to the user. The information can also be sent through a messenger.

f) Feedback Mechanism: The user keeps the information card for his use. In case he wants to consult the document, he tears off the request note strip and sends it to the library along with the response card, in which he indicates the degree of interest in the particular document.

g) Library Action: The library takes action on the request note strip to send the document(s) to the concerned user or to keep it in the library for him. The response card helps the library to know about the usefulness of the information provided as well as the shift in the information need. The library accordingly modifies the user profile page for improving performance.

4. Forms of SDI: SDI service may take the following forms-

a) Contents Alerts: This service is provided by photocopying, scanning the content pages of learned journals and other important publications keeping in view the interest of the users.

b) Routine of Periodicals (Automatic Loan): In this procedure, the current issues of periodicals are routed. There are two systems of routing the current issues of the periodicals. In the first method, the library sends the current issue to the first person on the last, who passes it on to the next name in the list. The last person in the list returns the periodical to the library. In the second method, the library sends the issue to the first person on the list, who returns it to the library, and then the library sends it to the next person on the list, who again returns it to the library. Next the library sends it to the third person, and the system goes on like this.

c) Notification of Forth Coming Conferences, Seminars, etc.: The information about forthcoming meetings, conferences, symposia, seminar, workshop etc. on a specific field should be notified to the members belonging to that specific domain. Keeping this purpose in view some library provides this kind of service to the user.


5. Conclusion: SDI refers to tools and resources used to keep a user informed of new resources on specified topics. Contemporary analogous systems for SDI services include alerts, current awareness tools or trackers. These systems provide automated searches that inform the user of the availability of new resources meeting the user's specified keywords and search parameters. Alerts can be received a number of ways, including email, RSS feeds, voice mail, Instant messaging, and text messaging.

Revision: This article was last edited on 5/12/2014.