As investigators of the past, historians rely on both primary sources and secondary sources. Primary sources are materials from the historical period being studied—government documents, numerical data, speeches, diaries, letters, and maps. Secondary sources are materials produced after the historical period that interpret or synthesize historical events.
The same source can function as either a primary or a secondary source depending on what you are writing about. For example, a newspaper article about John F. Kennedy’s decision to send troops to Vietnam would be a secondary source in an essay about why Kennedy made this decision. The same article, however, would be a primary source in an essay about newspaper coverage of Kennedy’s presidency.
Following are some of the ways historians use evidence:
For a research paper about the role of women in the British military during World War II, you might find evidence in women’s diaries and letters. If you were interested in how the government decided to create women’s military services, you could consult records of parliamentary debates or correspondence between military or government leaders. You could also find numerous books by other scholars with information on this topic.
For a research paper about attitudes toward Prohibition in different parts of the United States, you might consult regional newspapers or correspondence between politicians and their constituents. You might also find numerical data on liquor sales and Prohibition violations to support a hypothesis about regional attitudes.
For a review of several books about the fall of the Roman Empire, your evidence would come from the books themselves as well as other respected sources on the topic.
Related topics:
Conducting research
Supporting claims with evidence