Primary sources are documents, artifacts, or data created during the specific time period being studied. Oftentimes, documents from the first publication cycle – newspaper articles, letters, or research notes – are considered primary sources. Different academic disciplines have different definitions of what constitutes a primary source, which can make locating and identifying these sources a bit challenging.
While primary sources offer a firsthand account, secondary sources are written after the fact. Secondary sources analyze, interpret, explain, or analyze a primary source, event or individual. These resources represent a second publication cycle, tasked with presenting an argument or to persuade the reader. In a sense, they’re telling you what to think. Typically, journal articles are a good example. Criticism and interpretation are key functions of Arts and Humanities secondary sources. Social Sciences secondary sources interpret raw statistical data or provide commentary on social policies. Secondary sources in the Sciences are publications that review research or abstract it.
Tertiary sources organize information with the objective of making the information more accessible. This publication cycle attempts to be factual. Reference works such as dictionaries, encyclopedias and chronologies fall into this category. Indexes and abstracts are tertiary sources designed to help locate material on a specific subject or by a certain person. Readers’ Guide to Periodical Literature is a popular index often found in school and public libraries. All in all, the dividing line between secondary and tertiary sources is not always clear, the primary task usually being to single out primary source from other various source types.