Definitions: Primary, Secondary, and Tertiary Sources

Primary sources are artifacts, data, personal accounts of a time period, etc. These are the sources which a professional group studies and from which they draw conclusions. Primary sources are your best source of evidence. King's letter or Franklin's speech would be primary sources for rhetorical study, as would any act of communication.

Secondary sources are the collection of conversations folks are and have had about the primary source material or evidence. The rhetorical analysis you are writing and reading are secondary sources because they are made up of observations and analysis of primary source material. Other secondary sources might be articles or a professional conversation or email exchange. For instance, two nurses and a doctor might discussion what conclusions they can draw from a chart recording a patient's temperature, blood pressure, and pulse rate over a period of time.

Tertiary sources are those in which someone comes along and summarizes and compiles the conclusions made in secondary sources. Textbooks are a tertiary source, so are encyclopedias, so are most of what a professor says in a course. The doctor might take her own notes, those of the nurses, and summarize the differing opinions about a patient. This summary would them be a Tertiary conversation or source.

In most courses you learn what is known about a field of study--tertiary information--and you learn how to take the data studied by the courses discipline--primary source material--and construct and participate in conversations about this data. In this class, for instance, you are learning to take primary source material and analyze it using the techniques of basic rhetorical analysis. In most courses, you also learn how to read and judge (think critically about) secondary sources. You also learn how to produce new primary source material. You might, for instance, learn how to collect primary source data. For an example of such collection, think of a nurse learning to collect primary care data like pulse, temperature, and blood pressure.