Types of Information
There are three types of information. You may occasionally hear these called "source types" or hear a source called a "Primary" or "Secondary" source. Primary sources contain primary information. In some contexts, it's helpful to differentiate between different parts of a source. That's why we call them information types here.
Primary Information
Bain News Service, 1911 Library of Congress
Primary information is original. This can mean it is original evidence of a historical event, or that it was created as a result of original research. Primary information can also be creative, when poets or authors write poetry or fiction.
Examples can include:
- Journals, letters and photographs
- Novels, poems, plays
- Original research, notes & data
- Newspaper articles
Secondary Information
Secondary information is analysis of other information. Consider a common source of secondary information, the scholarly article. Scholarly articles often rely on primary information (the data researchers collected). The secondary information included in the research article is very important. This is the researcher's analysis of their data and how they situate their study in the existing research.
Examples can include:
- Literature critiques
- Biographies
- Scientific Reports
- Commentaries
Tertiary Information
Tertiary information is collected or distilled information. Tertiary is quite the word, so it's okay to think of this category as background or reference information. Tertiary sources condense a lot of information on a topic to just the high-level details. This can be very helpful when you're trying to get up to speed on a topic. It is also not an appropriate type of information to use as evidence for most college research.
Examples can include:
- Encyclopedias
- Chronologies
- Dictionaries
- Bibliographies
Wikipedia
Wikipedia is also a tertiary source. Wikipedia does differ in important ways from traditional reference sources. Wikipedia has a reputation for being unreliable. The truth is more complicated. Wikipedia has strengths and weaknesses, just like any source. Wikipedia can be edited by anyone. It also has a dedicated community of editors who undo malicious edits or additions without appropriate evidence. Errors aren't always caught immediately. Wikipedia can also be more up-to-date than traditional reference sources. It can also include information that is unlikely to appear in a traditional reference source and is freely available. Very generally speaking, Wikipedia is more likely to be incomplete than it is incorrect. Wikipedia should be used as a reference source with an understanding of its weaknesses. If that sounds complicated, it's okay to stick to library databases of reference material.