Criminal Justice

Primary, Secondary, and Tertiary Sources

Which type of information do I need?

Not all information sources are created equal for your research projects. Different types of research and writing projects will require different types of sources. Some disciplines will require you to use mostly primary sources of information. Some research or writing assignments will require secondary sources such as a book review or literature review. The following are definitions are the different types of information sources.* 

What is a primary source?

Primary sources contain first-hand information, meaning that you are reading the author’s own account on a specific topic or event that s/he participated in. Examples of primary resources include scholarly research articles, books, and diaries. Primary sources such as research articles often do not explain terminology and theoretical principles in detail. Thus, readers of primary scholarly research should have foundational knowledge of the subject area. Use primary resources to obtain a first-hand account of an actual event and identify original research done in a field. For many of your papers, the use of primary resources will be a requirement.

Examples of a primary source are:

• Original documents such as local, state, and federal laws in their original form, diaries, speeches, manuscripts, letters, interviews, records, eyewitness accounts, autobiographies
• Empirical scholarly works such as research articles, clinical reports, case studies, dissertations
• Creative works such as poetry, music, video, photography

Secondary Sources

Secondary sources describe, summarize, or discuss information or details originally presented in another source; meaning the author, in most cases, did not participate in the event. This type of source is written for a broad audience and will include definitions of discipline-specific terms, history relating to the topic, significant theories and principles, and summaries of major studies/events as related to the topic. Use secondary sources to obtain an overview of a topic and/or identify primary resources. Refrain from including such resources in an annotated bibliography for doctoral-level work unless there is a good reason.*

Examples of a secondary source are:

• Annotations and interpretations of local, state, and federal laws
• Publications such as textbooks, magazine articles, book reviews, commentaries, encyclopedias, almanacs

Tertiary Sources

A tertiary source is a distillation and collection of primary and secondary sources. Examples are:

• This libguide, or any research guide, published by a school, public, or academic library

*Definitions of primary and secondary sources are from the Research Process Libguide at Northcentral University Library.