Primary and Secondary Sources

Primary Sources

Primary sources are the most direct kind of information. They are original, firsthand sources created or written by persons directly involved in an activity or event. Different fields of study have different types of primary sources, but all of them are unanalyzed and uninterpreted. Examples of primary sources are autobiographies, diaries, notes, letters, emails, interviews, photographs, paintings, speeches, works of literature.

Secondary Sources

Secondary sources are one step removed from primary sources. They are opinions, commentaries, summaries, interpretations or evalautions of primary sources. Examples of secondary sources are biographies, interpretations of scientific discoveries, literature criticism, reviews of works of art, book reports, annotations and commentaries in anthologies, etc.

The distinction between primary sources and secondary sources can be ambiguous. A source maybe primary for one research paper and a secondary for another. It depends on the relationship of the sources to the research question. For example, the book, Abe Lincoln Grows Up by Carl Sandburg would be a primary source in a paper on the literary style of Carl Sandburg but a secondary sources in a paper on Abraham Lincoln. Time is often a defining element. A recent newspaper article is usually not a primary source, but it becomes a primary source when it is an article from the 1860s on the Civil War.

Below are more examples of primary and secondary sources in different fields of study.

Field of study Primary source Secondary source
Business NASDAQ stock quotes Historical stock analysis
Education Professor's lecture Treatise on teaching methods
Health Sciences Lab notes of scientific experiments Article on results of several clinical trials
Jewish Studies The Bible Rabbinic interpretations
Literature Sonny's Blues (short story) Critical character analysis
Psychology Patient interview videotape Psychological evaluations
History Slave diaries History textbook
Art Paintings of Claude Monet Magazine article on impressionist paintings


Selected websites with primary resources

The Library of Congress American Memory Collection

The American Memory historical collection is a digital record of American history and creativity. It provides free and open access to a rich database of written and spoken words, sound recordings, still and moving images, prints, maps, and sheet music that document the American experience.

Topics in Chronicling America

Chronicling America provides free access to more than a million historic American newspaper pages. Listed are topics widely covered in the American press of the time.

Ad* Access

An image database of over 7,000 U.S. and Canadian advertisements covering five product categories - Beauty and Hygiene, Radio, Television, Transportation, and World War II propaganda - dated between 1911 and 1955.

NYPL Digital Gallery

Provides free and open access to over 700,000 images digitized from the The New York Public Library's vast collections, including illuminated manuscripts, historical maps, vintage posters, rare prints, photographs and more. 

JNUL Ketubbot Database

The ketubbot digitization project aims to create a worldwide registry of ketubbot in public and private collections throughout the world. Based on the collection of the Jewish National and University Library with over 1600 items, the project contains ketubbot originating from dozens of different countries, and covering a time period of over 900 years.  It is a major resource for research in Jewish history, law and art.