Graduate Student Library Guide

It is important to understand the differences between types of sources.

Primary sources are sources created at the time of the event by someone related to the event. Primary sources within Humanities fields also include original works by philosophers, by artists, by novelists, by theologians, or by essayists. In the Social Sciences, Education, and STEM fields, primary sources are typically the first publication of the results of studies done by the authors of the study.

Secondary sources are journal articles, books, videos, etc. created by people who are removed from the original event or material by time, distance, or intellectual separation.  Secondary sources are often created well after the event when there has been time enough for reflection, additional details, multiple perspectives, or subsequent consequences to become apparent.  An important function of secondary sources is to permit objective evaluation, based on principles within a field of study, of the original event or material – to determine its significance, to analyze its causes, and/or to suggest the nuance of details of the event or material. Secondary sources typically propose interpretive arguments and their authors expect other scholars to question, examine, or even challenge those interpretations. 

Tertiary sources include lists, summaries, or concise descriptions of what is thought of as “existing knowledge” – things or events about which the details are firmly established.  The dates of an event, the name of an important individual, the physical description of a place or item which are not in question would be included in a tertiary source.  These sources typically fit into the “Reference Source” category: encyclopedias, handbooks, dictionaries, etc.  The function of this type of resource is to provide ready-to-hand knowledge which does not have to be memorized.