Saturday, November 29, 2014

Current awareness services (CAS) and selective dissemination of information (SDI)

इस ब्लॉग्स को सृजन करने में आप सभी से सादर सुझाव आमंत्रित हैं , कृपया अपने सुझाव और प्रविष्टियाँ प्रेषित करे , इसका संपूर्ण कार्य क्षेत्र विश्व ज्ञान समुदाय हैं , जो सभी प्रतियोगियों के कॅरिअर निर्माण महत्त्वपूर्ण योगदान देगा ,आप अपने सुझाव इस मेल पत्ते पर भेज सकते हैं -

Current awareness services (cas) and selective dissemination of information (sdi)

P- 15. Special and Research Libraries *

By :malhan v,Paper Coordinator


The modern libraries have started offering number of new documentation and information services. In this chapter we introduce you two important information services offered by special libraries and information/documentation centres: Current Awareness Services (CAS) and Selective Dissemination of Information (SDI).
  • Explain the need and purpose of Current Awareness Services (CAS);
  • Describe different types of Selective Dissemination of Information (SDI);
  • Explain the concept and objectives of Selective Dissemination of Information (SDI);
  • List the components of SDI with explanations;
  • Explain the functional aspects of SDI;
  • Highlight the importance of both CAS & SDI. 


This chapter entitled Current Awareness Service (CAS) and Selective Dissemination of Information (SDI) is written in three major formats. This begins with a general introduction describing the types of services rendered in the libraries along with the services dealing with the information regarding the current awareness in the specific field. Both CAS and SDI belong to these current awareness service categories. In the second phase CAS is described in detail along with its needs and forms of deliberations followed by SDI with the similar pattern.

Current awareness service generally means the information in brief regarding any particular topic or specific area of that topic. It depends upon the users specifications of information need lodged in the library profile. Mostly the awareness about title of the book, table of contents of the book, more extensively the brief reviews serve the primary purpose under CAS. These information can further be expanded depending upon users requirements and the ability, skill and eagerness of the library staff to serve. The mode of CAS traditionally was on print form by making photocopies of the table of contents and brief reviews served to the users. In that case the users are mostly benefited by being physically present in the institute, organization, college and universities. Due to advent of technology especially internet these information are being delivered through personalized mail, list serves and other bulletins. Presently the users need not to be present in the campus while availing the service. This is to be noted that this is a generalized kind of awareness where the users has to scan through their own relevant information.

Selective dissemination of information is also a kind of current awareness, rather not in a generalized format, but in selectively chosen information to the users matching with their information need. In this case a computerized data base is created with making two profiles. On the one hand a profile is created for users, named ‘user’s profile’, on the other the ‘document profile’ where different kinds of matching documents are listed. A computer generated matching is done with which user wants what kind of literature or resources. when it is matched  the matching information is send through email or a bulletin if the matching is large to the users. The only difference between CAS and SDI is CAS is a generalized information and the individual user has to scan his own where as SDI list of matching documents of a particular user. 


Literature growth in knowledge domain has great impact on every sphere of life especially in professional activities. This too has visible impact on librarianship profession especially in library services. This tremendous growth has put the information service providers in collection, processing and dissemination of desired information. At the same time the ethos of librarianship ‘right information to the right user at the right time’ is to be retained, despite the knowledge explosion in every discipline.

3.1.1    Library services

Library service is one of the key activities of any kind of libraries. Among these services the two key factors play important role; at the one hand getting ready with the processed information from which the users seek their information and gets satisfaction. This is a regular service often the traditional libraries most render. Another aspect which the special libraries most prefer this services among its users. It is to be noted that these special libraries and their users are needed to be abreast with new development in their respective fields at their earliest.

3.1.2    Information Dissemination   
Information seeking and dissemination by the libraries and library staff especially in case of special libraries has two aspects: Current Information
Current information is about the up-to-date knowledge in the area of interest, which is needed to be aware of recent development, so that researcher or user can give shape to his research accordingly and his time will be saved and engage them in other areas of research. This is popularly known as Current Awareness Service (CAS) by the librarian’s terminology. Required Information
This service provided by any libraries may be based on the exact information required by different types of users. This may be concern with the provision of answering of a specific query. In contrast to the above said CAS, this format may not be on recent development in the field rather from the entire resources available in the library and information resources. Mostly this service is tagged as Selective Dissemination of Information (SDI).

This is distinctly about the service matching with the exact requirements of the users. This chapter is all about two distinctive services of any libraries in general special libraries in particular - Current Awareness Service (CAS) and Selective Dissemination of Information (SDI). Further the chapter exemplifies the objectives, requirements, users and dissemination of information. 


As any definition is broad and too narrow, no definition on CAS has arrived at a consensus. According to Baradol, “The current awareness service is a service given by a library or an information centre to keep the users or clientele Up-to-date with the latest developments of their respective fields. It is known by different names, like Alert service or service for keeping Up-to-date etc (Baradol, 1997, p. 12).” This definition points out on up-to-date information. While highlighting the information from very birth of its origin Stauss el al says,  “ the establishment of a system for reviewing publications immediately upon receipt, selecting information pertinent to the programme of the organization served, and recording individual items to be brought to the attention of those persons whose work they are related. It involves a combination of processes including the selection of pertinent information from periodicals, books, pamphlets, patents and reports, in fact, anything of serious content that is received (Stauss et al, 1964, p. 144)." S.R. Ranganathan is of the opinion "documentation periodical ... listing the documents appearing during the period covered, and without being selected to suit the requirements of a particular reader or of a specific topic under investigation. This is of the nature of a general appetizer (Ranganathan, 1963, p.26).”

According Foskett, “current awareness service is of course a very descriptive title, which means what it says. Basically it means that someone examines every new item that comes into the library, not simply for the purpose of cataloguing it (important through that undoubtedly is) but also with the object of finding out whether it related directly to the new interests, the current work of any particular colleague (Foskett, 1975, p. 82).”  As per the Harrod’s librarians Glossary, the current awareness is, “a system and often a publication, for notifying current documents to users of libraries and information services e.g., selective dissemination of information, bulletin, indexing service, current literature. The term is sometimes used synonymously for SDI (1984, p.216).” 

A similar definition is given by Alasdair Kemp. He defines CAS as "a system for reviewing newly available documents, selecting items relevant to the needs of an individual or group, and recording them so that notifications may be sent to those individuals or group to whose needs they are related," According to him, CAS is "a system of informing the users as soon as possible after publication." (Kemp, 1979, p. 12).”   

All these above definitions provide us a consensus that CAS is meant for the immediate notice of newly acquired information in a specialized alerting mechanism form.

3.2.2    Characteristics of CAS
CAS is provided to update the knowledge of researchers and users in the area of his/her expertise. This is a continuous activity by the libraries/library staff in uninterruptive ways. Because the break in this service may lead a gap in their orientation to the areas of interest or work. This service may fulfill and ensure the users not to be left with any information of their desire unknown. Further, this avoids duplicity. All these characteristics can be summarized:

  • CAS meets the current information requirements;
  • CAS is provided to a similar group of users/researchers on the basis of their common information requirements;
  • CAS not necessarily matches to the specific requirement of a user. It is simply current information. The information dissemination may in the form of print tools (but no more in trend) rather electronically.
  • Its deliberations are within the stipulated time framed and pre-known to the users. It may be daily, weekly, or on the basis of fortnightly.
  • Specific feedback is not required as its nature is simply current awareness in required or related areas.
  • CAS facilitates in quick awareness since the inception of particular information as it takes time to be availed through any other sources (indexing & abstracting journal, commercial catalogue, marketing sources etc)

3.2.3    Need
The advent of technological developments have given changes in thoughts of human minds at the same time services available through these technologies especially internet and its related field has made easier to access any kind of literature at any time. At the same time development in the subjects and research in interdisciplinary areas are the development of the days. The researchers need the recent development in their field earliest probably since the origin of information. The information has to be disseminated promptly to the researchers for their research work. So prompt dissemination needs current awareness service. At the same time large quantity of information which is available and in being generated daily makes it difficult to keep the users abreast with the recent developments in the respective fields. So the need CAS has become very vital. The traditional services including the old pattern of indexing and abstracting services or generalized documentation are too broad for any individual library as well too large to digest these heavily loaded resources for any researcher. At the same time it is time consuming to reach at the end users. Language consideration is also another concern though rare; by the CAS locally generated resources can also be helpful. Tumer is of the opinion that , “the poor currency of traditional abstracting services promoted the publication of current awareness publications with time lags of weeks instead of months  (Tumer, 1962, p. 24).” 

3.2.4    Historical Development
Though difficult to trace the historical development of CAS services in the libraries, but Whitehall’s opinion could help us in reaching at a point of origin. “The golden age of current awareness service was most probably the early 1960s. At that time the larger companies began to like chemists, engineers and biologist to work in or alongside their libraries, or they transferred staff from the laboratory to libraries, in order to hav people who could read the vast amount of technical literature and recognize ideas of value to the research and development effort (Whitehall, 1986, p. viii).”  Since then these CAS services has become a common phenomena in the libraries across the world especially due to popularity of internet and its related fields. Less cost in sending the printed resources has vanished due to these technologies. Though some libraries name it in a different way but it is common in all types of libraries and bitterly found in special libraries.

A current content is published by the institute for scientific Information (ISI) Philadelphia (USA) in the following subject groups:

(a)    Agriculture, Biology and Environmental Sciences (AB and ES)
(b)   Arts and Humanities ( A and H)
(c)    Clinical Medicine (CM)
(d)   Engineering, technology and Applied Sciences (ET and As)
(e)    Life Sciences (LS)
(f)    Physical, Chemical and Earth Sciences (PC and ES)
(g)    Social and behavioural sciences ( S an BS)

Looking at the contemporary scene in the special libraries of India the CAS services in its diversified forms are plenty, probably in some cases heavily dominated in government funded special libraries. The brighter example of these services is found in CSIR institutions.

3.2.5    Types of CAS
1. Current awareness bulletin
2. Research in progress
3. Conference alert
4. Selective Dissemination of Information (SDI)
5. Newspaper clipping service
6. Title and table of content announcement services. 

3.2.6    Future
It is indisputable to affirm CAS service is inevitable for any libraries and special libraries in particular. To provide and to avail this service has become easier for friendly of internet services both at service giver and consumer. Without this research scholar, scientist or any academicians would have to wait through piles of books and research papers. This service serves in form of shortcut and qualitative awareness about the recent developments in the field required by any individual user. This also saves the time of the users in return it develops the productivity of the scientist and technologist. In this sense the special libraries are doing good jobs and they need to enhance this particular CAS service in further better ways. 


SDI is a type of current awareness service meant to keep the user abreast with the latest developments in the field of his interest. It is a personalized service meant for the individual or a group of users having identical information needs. It is a quick service which provides the pinpointed and exhaustive information to the users. SDI involves the screening of the document and selecting the information according to the specific information needs of each user or group of users (homogeneous). The main objective is to keep the user well-informed and up-to-date in his area of interest.
3.3.2    Definitions
By definition, dissemination refers to distribution of information to the users. This information could be of any type and its subtypes. According to Routledge International Encyclopedia of Information and Library Science, “active distribution and the spreading of information of all kinds are called dissemination of information. It concerns metadata as well as primary sources (Routledge…, 1997, p 1987).”  This service is provided by libraries whose particular information, requirements is previously determined. In this case in librarian’s terminology Selective Dissemination of Information (SDI) is frequently used. The basic objectives are to pass users on with all the latest information exclusively matching with their requirements and this service is to take place at a regular and fixed intervals.  The evaluation criteria should match to the satisfaction of the users. And the feedback gives the opportunity to improve and have control over the accuracy. The profiles of users’ interest or the target group stored in a computer generated system with its updation and their profiles are further matched with the resources available through the libraries and information centres. These activities are frequently and largely visible in special libraries.

H.P. Luhn of IBM is believed to have used this SDI for the first time. “The Selective Dissemination of Information is the service within an organization which concerns itself with the channeling of new items of information, from whatever sources, to those points within the organization where the probability of usefulness in connection with current work or interest is high. On the other hand, the service endeavours to withhold such information from the points where this probability is low (Luhn, 1961, p. 135). "
Selective Dissemination of Information (SDI) is defined as the system in which automatically generated matching information is disseminated to researchers, scholars and users.

3.3.3    Characteristics of SDI Services
The following are few important characteristics of SDI service:
1.         SDI is personalized information service;
2.         SDI is also a CAS service.
3.         SDI is exact information matching service required by the users;
4.         SDI can be improved by successful feedback.
5.         SDI is largely used by profiled researchers;
6.         SDI is largely visible in special libraries.

3.3.4    Need
This selective dissemination of information (SDI) is a value added service for the users not only save the time and the avoidance of information overflow through a regular supply of latest information, for any research and professional practice. Sometimes even the users who never would be able to or willing to keep themselves abreast with new information can be supplied with current information through this practice. This SDI is an effective means to improve the level of information used by the users which further allows them in making their decisions on a well informed basis.

3.3.5    Historical Development
Traditionally speaking libraries and information centres were restricted gathering, organizing and providing information to the users. However, special libraries and documentation centres expanded their basic functional activities by adding this SDI services. The changing phases from industrial society to information society gradually affect the library functions. So the libraries started integrating services with disseminating information in many ways which later on tagged as SDI services. Some kind of tailor made services was designed for the individual or group of information profiles. The marketing features of libraries allow the growth of relevant services that are adapted regularly to the user’s requirements. Once dissemination of information or SDI offered by libraries or rather special libraries was restricted to only library – owned materials. But now electronic media especially internet has made possible to access any kind of resources located anywhere across the world. The results of internet platform, subject gateways, subject portals or information co-operatives of scientific and special libraries head in this direction as a result active SDI is better possible.

3.3.6    Forms
The intensity and forms of SDI services vary from libraries to libraries depending upon the quality and quantity of the users. At a very primary level current journals and reports or their tables of contents are circulated to the users whose information profile they match. Sometimes externally generated bulletins and CAS services that are made and offered for matching profiles can be subscribed and distributed by the special libraries. Here the role of the libraries is to mediate between the source profile and the individual profile.

All the relevant sources including the printed bibliographic data bases and electronic sources are regularly scanned and evaluated for this purpose by the trained library staff. The profile matching the selection and compression of relevant information is also done by specific section of libraries. Methodologically these activities are done through intelligent or trained people so that selection and matching is done perfectly. Default profiles or individual information profiles is stored in the data base and spread into the search vocabulary of the respective sources. Through mechanisms intelligent agents, filters facilitate this improvement of dissemination of information. An appropriate methodology of generating and maintaining and adopting the individual profiles of interest is basic to this effective SDI with an extensive thesaurus or any subject lexicons the users find to select a number of descriptors or key words. And sometimes the users instead common terms for their key terms of interest. Then the information specialist in the libraries convert these common terms into standardized descriptors which librarians often say controlled vocabulary to produce exact information profiles. To avoid uncertainties a regular feedback system is to be their in the SDI service system. Further interest profile of the users can even be personalized or tailored to a target audience sometimes numerous individual profiles coincidently match with each other’s interest. In that case an information bulletin can even be created. This homogeneity in profiles often found in a large laboratory where researchers work on a particular field. For an example in an Indian scenario council of scientific and industrial research CSIR has number of research labs or institutions devoted to a specific kind of research e.g., potato research, rice research, metallurgy research, arid crop research etc. Here the homogeneity in information profile is to be common. However this is not true heterogeneous profile which requires very personalized dissemination service. In large institutions especially universities where both research on science social science and humanities are conducted, in IITs of India a combination of both the alternatives are offered.

Any SDI system has the following basic components:
1.         User profile: A set of user profile consists of file, describing the subject interest of the user. It is a computer readable file. The terms used in describing the user interests are also drawn from the same indexing vocabulary (thesaurus) as used in document database (document profile). It ensures good matching of user interest with document contact.
2.         A document profile or database: It consists of a file that contains documents description and terms respecting the content of the document. Document database is in a computer readable form. It is used for recent or current literature. The terms or keywords chosen to describe the contents of the document are usually drawn with the help of thesaurus

The content of dissemination of information services can include metadata and primary sources published and informal sources also. But in case of metadata it should be in detail inclusive of annotations and abstracts in such a way so that the users are enabled to decide whether ordering, reading or printing is cost worthy. Previously the SDI services occurred through newsletters, information bulletins and sometimes individual messages in printed way. But these days such bulletins and newsletters are offered through online mode and many a times through e-mail notification. These SDI services provided are to be based on simple and clarity so that the users can use it as value added service without much time and cost. At the same time the design of the products of SDIs is to be made on a friendly and readable way.

3.3.7    Future
In contemporary scene SDI service has made its way commonly to special libraries and limping to other library sectors including academic libraries. The trend to produce such services has to be on cooperative basis by the library staff and the users. Though commercial providers have already entered into this still the users believe in the service rendered by their own libraries. International brands emerald, Elsevier, and other brands are already on the market. The users also are to be alert and not to be too vague for generating their individual profiles. The best possible way is to be guided by the available internet portals so that a specific and possible descriptor can be chosen. This SDI service would be of a high value service if it is closer to personalized service between the provider and the user. This SDI service has become so popular in certain cases the user’s specially profiled scientist fully believes on this and certain libraries are exclusively known for this SDI services

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