Introduction: Evaluating Sources

What's in a source?

This tutorial introduces you to the different types of sources that you will study for and cite in your written assignments in college. Learning how to evaluate sources of information is essential to becoming an educated person. You will not use all the types of sources mentioned below in the same way, nor do all sources within each catagory have the same authority. This tutorial will help you learn the differences among the types of sources available in the library, and prepare you for the next step, which is research.

Three Types of Sources: Primary, Secondary, and Tertiary.

1. Primary: Primary, or original sources, are those that are considered the least "corrupted" by interpretation. In other words, they are original to the information to which they refer. Examples of primary sources are letters, diaries, contracts, meeting minutes, and raw data collected for a formal study.
2. Secondary: Most of the sources you learn about in this tutorial are secondary. Secondary sources are those sources that interpret either raw data or other secondary sources for the reader. Examples of secondary sources are books and articles (magazines and scholarly journals), although primary sources may be reprinted in book or article form.
3. Tertiary: Tertiary means "thrice removed" from the origin. In other words, a tertiary source may cite primary and secondary sources, but it usually relies on the authority of specialists, and often times a variety of specialists. Examples of tertiary sources are reference works like subject specific encyclopedias and dictionaries.