There are three main types of sources you can use to research historical topics: primary, secondary, and tertiary sources.
A primary source is material that records a first-hand account of an event and are usually produced by people who witnessed or were involved with the event. Primary sources can also include sources created at the time of an event but are not first-hand accounts, such as newspaper or magazine articles. Although these are not first-hand accounts, they can provide insight into how historical events were discussed and understood at the time. They are original materials that have not been modified by interpretation and offer original thought or new information. Examples include memoirs, interviews, accounts that were written later (journal/diary entries), artwork, literature, objects, government documents, and many more.
A secondary source is one that analyzes primary sources to interpret historical events or themes. Secondary sources can include books, articles, or documentary films. Published collections of primary sources sometimes include secondary source introductions that explain what the primary source is. It can describe physical features and discuss its significance in helping us understand an event or topic. These resources often present primary source information with the addition of hindsight or historical perspective. Common examples include criticisms, histories, and magazine, journal, or newspaper articles written after the fact.
Tertiary sources are sources that identify and locate primary and secondary sources; their chief purpose is to list, summarize or simply repackage ideas or other information and they do not add any additional interpretation or analysis. These can include bibliographies, indexes, abstracts, encyclopedias, and other reference resources. These types of sources may also provide information that informs us of the consensus on a topic, or it may summarize the various arguments happening around a topic. This definition also applies to many museum, library, and other educational websites or popular sources.
It can be helpful to think about these types of sources occurring in layers.
Layers of Historical Research Sources
Layer 1: Primary Sources Diaries, letter, art, government documents or other materials from the period you are studying.
Layer 2: Secondary Sources Books, journal articles, and essays that provide original research and analysis of primary sources.
Layer 3: Tertiary Sources Encyclopedias, Wikipedia, library or museum websites that collect and summarize multiple primary and secondary sources.
Evaluating your sources ensures that they are appropriate for the context in which you will use them and that they are reliable, which will support your work. It allows you to be credible as you engage in research and participate in the scholarly conversation in your field.
There are different methods and strategies -- two are explained below -- you can use to evaluate the information you find on the internet and in libraries, but there are three main questions you should ask yourself:
You should also monitor your emotional response to sources and check out why they make you feel a certain way: are they confirming, or confronting your pre-existing worldviews?
Lateral reading is looking at other sources to provide context for the source you are evaluating. For a website or webpage, this means opening new tabs in your browser to search for information about it, rather than simply looking at the design, the URL, and the "About" page of the site.
To evaluate a website, webpage, video, image, or social media post, you can see what the following sources say about it:
Take into account that many news organizations have their own perspective and even media fact-checking involves subjective judgments, it is a best practice to look at multiple sources.
The SIFT method was created by Mike Caulfield to help you determine if sources are credible. It is a mnemonic device that stands for Stop, Investigate the source, Find better coverage, Trace claims, quotes, and media back to their original context.
All SIFT information on this page is adapted from Mike Caulfield's materials with a CC BY 4.0 license.
Because primary sources are unfiltered records of the past, we must examine these sources with a critical lens to better understand the period, people, and perspectives represented. Below are questions to consider when evaluating primary sources:
