Secondary sources

A secondary source is based on information that has originally been presented before, usually in a primary source. This information is not based on first-hand experience. A primary source might focus on only one event, but a secondary source can examine this event in relationship to its time period, the people involved, and other events that preceded or followed it. Secondary sources enlarge upon primary sources, often explaining why an event was important or examining the cause and effect relationship of a series of events.

Depending on how they are used, secondary sources can also function as primary sources. For example, a history written in the 1800s can provide evidence of the worldview of that period.

It is important to analyze information presented in secondary sources critically, since they sometimes support particular opinions or viewpoints–that is, they can be biased. Analyzing a secondary source is similar to analyzing a primary source.

History texts, biographies, textbooks, and encyclopedias are all examples of secondary sources.