Types of Sources

Primary v. Secondary v. Tertiary Sources

Sources of information or evidence are often categorized as primary, secondary, or tertiary material. This classification is based on the originality of the source or its proximity to the source of origin. This classification also helps us determine whether the source is a first-hand account or rather a retelling of the experiences or opinions of others, in which case that would be considered second-hand information. 

Determining the differences between the types of sources can be a bit tricky, especially considering that they can vary from discipline to discipline. Hopefully this general guide will help you gain a better understanding of their differences.

PRIMARY SOURCES

A primary source is any type of documentation that is original to a person or an event, meaning they are being reported first-hand without any interpretation or commentary. 

For example, primary sources include original documents, first-hand accounts, images, objects, government reports, or original, creative work. 

Original documents: Diaries, speeches, letters, correspondence, interview transcripts, news footage, autobiographies, reports, conference proceedings, census records, or statistical data derived from an experiment 

Creative works: Poetry, plays, photographs, novels, music scores, films, or paintings

Objects: Clothing, building, tools, or furniture 

SECONDARY SOURCES

A secondary source is a work that analyzes, assesses, or interprets a historical event, era, or phenomenon, or in other words, explains a primary source. These sources tend to not only summarize, interpret, reorganize, or provide added value to a primary source, they can also be used to support an argument or to persuade an audience. 

For example, secondary sources include journal articles, editorial articles, book reviews, biographies, or textbooks. 

TERTIARY SOURCES

Tertiary sources are sources that index, abstract, organize, compile, or digest other sources. When the main purpose of reference materials or textbooks are to list, summarize, or repackage ideas/other information, they can be considered tertiary sources. They are also not typically credited to any particular author.

For example, tertiary sources include Wikipedia, abstracts, dictionaries, encyclopedias, almanacs, fact books, directories, guidebooks, manuals, handbooks, and even library databases or catalogs.

Note: Tertiary sources are very helpful at the beginning of your research process – utilizing these can help you identify keywords for your searches or to establish background information. However, they should not be heavily relied upon as the bulk of your research should focus on primary and secondary sources.