Historians use different types of sources for different purposes. Understanding the differences will help you locate the best evidence for your research.  

Primary Sources

Primary sources are original, firsthand accounts created by people who experienced or witnessed an event. They provide direct evidence from the time period being studied.

Examples:

• Letters written by Mary Todd Lincoln during the American Civil War
• A Vietnam War soldier's journal
• Photographs of the Hindenburg disaster
• Government documents, speeches, diaries, and newspapers published during the event
   

Secondary Sources

Secondary sources analyze, interpret, or explain primary sources or historical events. They are at least one step removed from the original event and are the types of sources you will use most frequently in college research.

Examples:

• Scholarly journal articles
• Books written by historians or other scholars
   

Tertiary Sources

Tertiary sources summarize, organize, or compile information from primary and secondary sources. They provide background information and help researchers locate additional sources, but they generally do not present original research or interpretation.

Examples:

• Encyclopedias
• Dictionaries
• Library research starters
• Handbooks

As you conduct research, think about how your sources work together.

Ask yourself:

• How do my sources connect to one another?
• How does each source support, explain, or expand my understanding of the topic?
• Which sources provide evidence for my research question?
• How do my sources support my thesis or overall argument?
   

Before using a source, consider whether it is reliable, relevant, and appropriate for your research.
 

1. Purpose and Context: Consider why the source was created and how it fits your research.
2. Credibility: Evaluate who created the source and where it was published.
3. Evidence and Verification: Reliable sources support their claims with evidence.
4. Perspective and Bias: Every source reflects a particular perspective. Rather than dismissing a source because it contains bias, consider how the author's perspective shapes the information presented. Recognizing bias allows you to evaluate evidence more critically and understand different interpretations of historical events.

Bias is a preference, viewpoint, or perspective that influences how information is presented or interpreted. Every source has a perspective shaped by the author's experiences, beliefs, purpose, or historical context.

Recognizing bias helps you:

• Better understand an author's point of view.
• Evaluate the strength of the evidence presented.
• Compare multiple perspectives on the same historical event.
• Develop a more balanced and informed analysis.

Bias
A preference or point of view that influences how information is presented or interpreted.

Context
The historical, cultural, political, or social circumstances surrounding an event or source.

Primary Source
An original document or firsthand account created by someone who experienced or witnessed an event.

Secondary Source
A source that analyzes, interprets, or explains primary sources or historical events.

Tertiary Source
A source that summarizes or organizes information from primary and secondary sources, such as an encyclopedia, index, or handbook.