Sources of information

On this page, we will discuss what kind of information sources are commonly used in scientific and academic research.

Information sources are printed, electronic or e.g. orally narrated information on which research or some other scientific presentation is based. Information sources are also used for such purposes as creating an overview of a subject matter, searching for data and learning the terminology of a field.

Primary and secondary sources

Information sources can be divided into two categories according to their degree of originality: primary and secondary information sources.

Primary sources contain new information expressed for the first time or in full.
Primary sources:

  • Doctoral theses and research reports, for example, are primary sources that are often used.
  • Articles that report new research results are also primary sources, published in scientific journals that concentrate on a certain field of research. Some of the scientific journals peer review articles to ensure scientific quality. Experts in the field often check and accept the articles. In natural sciences and medicine, for example, journal articles are the most commonly used primary sources.
  • Journals may also contain review articles that present and comment older research, reviews of research publications, and discussions. Such articles do not fill the criteria for primary scientific and academic sources.
  • In some fields, e.g. arts and theology, the primary sources are often books.
  • In some fields of the arts and social sciences, we can speak of primary or original sources when speaking of documents that are the object of research (such as letters, diaries, magazines, comic books). They are also often called source material so as not to confuse them with primary academic publications that present new research.

Secondary sources summarize and structure the information in primary sources, and help you to find them. The most commonly used secondary sources are:

  • literature references
  • summaries
  • reference books (manuals, dictionaries and encyclopaedias).
  • text books.

Reference books can make it easier to find information by ordering the core information of a certain subject area under certain search terms. Reference books give a straight answer to questions about a certain subject area. They can also help you form an overview of a subject area or teach you the terminology of it.

During a research process, you can also use secondary sources as stepping stones for finding further sources of information. It is important to review all source materials with a critical eye, particularly if the information is available on a website that is not edited by a team of experts. Wikipedia is a collaboratively created website where anyone can contribute. Wikipedia should not be a primary source in scientific research.

The context of a study determines what source material is suitable for examining the research object.

In order to ensure that your source material is reliable, use primary sources as much as possible in your scientific and academic work.

More information about publication types in Oulu University Library guide.


Data is collected, sorted and stored in different databases. It is easy to search for information in a database, since the information is sorted into well-defined fields to which the searches are directed. You can use discipline-specific guides to find suitable databases for your topic.

For an information-seeking approach, databases are often divided into full-text, fact and reference databases.

Full-text databases contain the full text of publications, e.g. articles from books or journals, research reports, theses, reference books or books. The advantage with full-text databases is that you can access the publication you want directly.

Fact databases contain factual data in the shape of numbers, images, text, etc. and they give a straight answer to questions about facts. Statistical databases and different indexes are examples of fact databases.

Reference databases contain reference data of publications as well as an abstract of each publication. The reference data includes the bibliographic data and words that describe the main contents of the publication, such as descriptors, subject headings and classification codes. You can use the reference data to find a publication.

Actually, many databases are combinations of full-text and reference databases – some publications are fulltext, while others have only bibliographic data.

The following image shows an excerpt from a reference database (the Medline database):