1. Introduction to Information Sources
Information sources are many and varied, encompassing everything from human beings to physical documents and electronic files. Over time, the methods of recording and communicating information have evolved from cave paintings and oral traditions to handwritten manuscripts, printed books, and now, electronic media.
In library and information science, these sources are broadly divided into two main categories: documentary and non-documentary sources. This categorization helps in understanding how information is created, organized, and disseminated.
2. Documentary Sources
Documentary sources are defined as all sources that exist in the form of a document. The term "document" has expanded over time to include not only traditional printed materials but also manuscripts, videotapes, computer files, and databases. These sources can be further categorized based on their content, publication status, and physical form.
2.1 Categorization by Physical Form
- Print Sources: These are all sources that exist in printed form. Examples include books, periodicals, patents, standards, reports, and newspapers.
- Non-Print Sources: This category includes all documentary sources that are not printed. This is a broad category that covers both traditional and modern formats, such as:
- Handwritten or typed materials like manuscripts, theses, diaries, letters, and office files.
- Microforms.
- Audio-visual materials like audio and video recordings.
- Electronic sources, a major and growing category, which includes CD-ROMs, databases, computer files, and e-publications.
2.2 Categorization by Publication Status
- Published Sources: These are documentary sources, both print and non-print, that are produced and distributed by a publisher, usually in multiple copies and for sale. Examples include books, periodicals, standards, and commercially available databases and CD-ROMs.
- Unpublished Sources: These are documentary sources that are not formally published or produced in large numbers and are typically not for sale. Examples include manuscripts, theses, project reports, diaries, letters, office files, laboratory notebooks, and medical records.
2.3 Categorization by Content (Primary, Secondary, and Tertiary)
This is the most common way of classifying documentary sources, based on the originality and organization of the information they contain.
Primary Sources:
- Definition: A primary source contains newly generated information, original research, or a new interpretation of known facts. It is the first and often the only published record of original work. The information in primary sources is often scattered and unorganized.
- Examples: Research periodicals, technical reports, conference proceedings, patents, standards, theses and dissertations, official publications, trade literature, unpublished materials like laboratory notebooks, diaries, internal research reports, correspondence, personal files, and medical records.
Secondary Sources:
- Definition: A secondary source is one that is dependent on primary sources for its existence. It gathers information from primary sources and organizes it according to a definite plan. Secondary sources often act as a key to accessing primary sources.
- Examples:
- Secondary Periodicals: These include abstracting periodicals (Chemical Abstracts), indexing periodicals (Index Medicus), reviews of progress (Annual Review of Immunology), and popular periodicals (Science Reporter).
- Reference Books: This is a large category that includes encyclopedias, dictionaries, handbooks, manuals, yearbooks, almanacs, directories, gazetteers, biographical sources, and atlases.
- Other examples: Bibliographies, treatises, and textbooks.
Tertiary Sources:
- Definition: A tertiary source is one that is dependent on secondary sources, or a mix of primary and secondary sources, for its existence. These sources act as a key to both primary and secondary sources.
- Examples: A bibliography of bibliographies, a directory of directories, guides to the literature (or guides to reference sources), and library catalogues.
2.4 Ranganathan's Categorization
Dr. S.R. Ranganathan offered two other ways to categorize documents:
- By Volume of Thought Content:
- Macro Documents: Documents embodying macro (large) thoughts, such as books.
- Micro Documents: Documents embodying micro (small) thoughts, such as journal articles, which are often contained within a macro document.
- By Recording Media:
- Conventional Documents: Documents where paper is the basic material for recording, such as printed books and journals.
- Non-conventional Documents: Documents reproduced on non-paper material (e.g., microfilm) or those that record sound and/or pictures (e.g., audio-visual materials).
3. Non-Documentary Sources
Non-documentary sources of information are those not contained within a physical or electronic document format. They are often considered close allies of documentary sources and are crucial for obtaining current, practical, or unrecorded information. They can be broadly grouped into humans, institutions, and media.
Humans: Every sensible human being is a source of information. This includes:
- Core Information Professionals: People whose job is to generate, gather, process, or disseminate information, such as researchers, inventors, reporters, compilers, editors, translators, and librarians.
- Peripheral Information Professionals: Experts in other fields who act as vital information sources, such as lawyers, doctors, and teachers.
- Other Human Sources: This includes consultants, extension workers, technological gatekeepers, members of an "invisible college" (an informal network of scientists), and common people who possess valuable local or experiential knowledge.
Institutions/Organisations: Institutions are major sources of information through their activities, publications, and personnel.
- Examples: Government ministries and departments, international agencies (like UNESCO and WHO), R&D organisations, academic institutions, learned societies, publishing houses, press and broadcasting stations, museums, archives, and non-governmental organisations (NGOs).
Media: Mass media, including both print (newspapers, magazines) and electronic forms (radio, television, films, recordings), are powerful channels for disseminating news, entertainment, and information to a wide audience. They are invaluable primary sources for recording contemporary history.
World Wide Web: The Web is listed as a distinct non-documentary source, acting as a vast, interconnected environment for information.
4. The Role of Electronic Sources
Electronic sources are not a separate category but a format that pervades all other categorizations. The "growing importance of information and its presence in electronic form" has transformed the information landscape.
Electronic Documentary Sources: Many traditional print documents now have electronic counterparts. Libraries are increasingly becoming "hybrid," with a mix of print and electronic collections. Examples include:
- E-journals and E-books.
- Databases (bibliographic, full-text, numeric) available online or on CD-ROM.
- Digital Libraries and Institutional Repositories which store and provide access to digital collections.
- Digitized materials, where print documents are converted into a digital format through scanning and OCR.
Electronic Non-Documentary Sources: The primary example is the World Wide Web (WWW), which is a global, non-documentary source of information. Electronic media such as radio, television, and podcasts are also key non-documentary sources. The development of ICT is central to the creation and dissemination of these sources.