We posted previously about Primary and Secondary sources, but there is another type of source that you may use for your dissertation research: tertiary sources.

What is a Tertiary Source?

As the University of California Irvine library explains, tertiary sources collect, distill, and identify information from primary and secondary sources. Think of it this way: A primary source is new, raw data that hasn’t been analyzed. A secondary source is one in which an author analyzes data from primary sources. A tertiary source summarizes primary and secondary sources.

Tertiary sources typically do not advance an explicit argument, and instead summarize existing knowledge and arguments. However, even if there is no explicit argument, a tertiary source may still exhibit a particular bias, depending on which primary sources and secondary sources the author uses.

What Kinds of Documents Count as Tertiary Sources?

Dictionary and encyclopedia entries are among the most common forms of tertiary sources. Other tertiary sources include directories, guidebooks, and textbooks. The University of Maryland Library has a helpful discipline-by-discipline breakdown of different kinds of tertiary sources.

Note that some encyclopedia entries, dictionary entries, etc. might be considered secondary sources – it all depends on how many steps away from a primary source you are. Sometimes, biographies also count as tertiary sources, depending on the kind of research that the author conducted. Our dissertation research consultants can help you evaluate whether or not your sources are primary, secondary, or tertiary.

How can Tertiary Sources Help My Dissertation?

Tertiary sources are mainly useful as a starting point, and for gathering information. If you are a historian, for instance, you may look up a particular historical figure in an encyclopedia to find out basic background info. In this way, tertiary sources can help you understand the context and background of your dissertation topic. You cannot, however, build an entire dissertation around tertiary sources. Depending on your field, you may be expected to find and analyze your own primary sources in your dissertation. You may also be expected to engage with or critique arguments from secondary sources. Our dissertation research consultants can help you determine the appropriate way to use sources in your dissertation.

If you need research help, we are here for you! A dissertation consultant or a dissertation advisor can help you plan your research strategy, or you can take advantage of our dissertation research services. When you’ve done your research, we can provide professional dissertation editing services to make sure that you turn in a perfect draft. And finally, we can help you format all of your citations using accurate APA, Chicago/Turabian, MLA, or Harvard Bluebook style.