Students often have trouble identifying primary, secondary, and tertiary sources for research. To understand the difference, think about where information originates and how it evolves through the publication cycle. 

Also keep in mind that sources may also change categories depending on your research objective.  Information considered as a primary source for one research project could be used as secondary source in another research project.  Therefore the examples in the chart below are not set in stone.  The chart is only meant to help you with the general concepts.  ALWAYS ask your teacher for clarification if you have any doubts about a particular source.

Primary

Secondary

Tertiary

What is it?

Original, unevaluated, non interpreted, direct evidence records on the subject of your research project 

Reviews, analyzes, evaluates, interprets, retells primary sources

Compiles, summarizes, reviews secondary sources.  Usually factual in nature.

Where is it in the publication cycle?

Usually first

Second

Last

What are some examples?

Artifacts
Autobiographies
Books, journal or newspaper articles written at the time of the event by an observer
Conference Proceedings
Correspondence
Diaries
Government Publications
Interviews
Manuscripts
Poetry
Recordings (audio or video)
Song Lyrics
Speeches
Web sites providing original research, ideas, collected writings and recordings.

Biographies
Books, journal or newspaper articles, or electronic materials providing criticisms, commentaries, analysis, or interpretations of subject or event
Law / Legislation
Web sites commenting on earlier research

Almanacs
Atlases
Dictionaries
Directories
Encyclopedias
Guidebooks
Handbooks / Manuals
Indexes
Statistics
Tables