It’s important to understand the main types of sources when you’re doing research. Different topics and arguments call for different types of data, and that data is located in different places. For example, someone doing research on climate change would want to locate sources devoted to that topic. Knowing the differences between the types of sources will make you more efficient at deciding what kind of information you need to support your claims, and where to find it. Sources fall into three main categories: primary, secondary, and tertiary. This post will cover them each, as well as the more specific types of publications within them.
Primary Sources
Primary sources include information without much or any interpretation. You can think of it as raw data or firsthand accounts of the world. Commentary in primary sources will only offer the most basic help to understand the significance of the information provided. It doesn’t try to influence you one way or the other — at least not explicitly. There’s always a chance that a study or poll could have inherent bias in data collection.
Primary sources often include interview transcripts, speeches, observations, case studies, and statistics — especially from trusted organizations and government institutions. They include the following: FBI, CDC, FDA, The Bureau of Economic Analysis, Bureau of Justice, Bureau of Labor Statistics, Bureau of Transportation Statistics, the Census Bureau, Economic Research Service, The National Center for Education Statistics, and the National Center for Health Statistics. You can access government data through data.gov, as well as here: Other organizations commonly collect and present data on a range of public policy issues. They include the PEW Research Center, Gallup, and McKinsey & Company.
You can access raw data from a variety of agencies and institutes from services like ProQuest Statistical Insight, Statistica, NationMaster, Harvard Dataverse, World Bank DataBank, Mergent Online, UNdata, UNESCO Institute for Statistics, Wikidata, and the Inter-University Consortium for Political and Social Research. These are all trusted entities that collect and organize data for writers and researchers.
Primary sources also include original historical documents like letters, manuscripts, diaries, memoirs, field notes, interviews, ethnographies, speeches, historical newspapers and periodicals, photographs, paintings, and artifacts. You can access these through a range of online historical collections like the American Periodicals Series, British Periodicals, and Artstor. You can visit the Center for Research Libraries and the Organization of American Historians for lists of historical societies and special collections. You can also ask library research specialists for help.
You can always collect your own primary data. You can interview people on a topic and use that as a source. If you want to research ways people interact in online discussion forums, then their comments would qualify as primary data. You could also treat posters, artwork, tweets, and even YouTube videos as forms of primary data. For example, if you wanted to write a paper on influential YouTube personalities, then you would systematically gather and analyze their posts for insights.
Secondary Sources
Secondary sources offer opinion and interpretation along with their information. These sources help guide and support your analysis of primary data. They help shape our knowledge of the world, and they can even point you toward other helpful sources of information. For example, existing articles on YouTube and social media could help you frame your discussion and analysis of YouTube personalities.
Secondary sources include blogs, newspapers, magazines, and academic journals. The specific types of secondary sources you need will depend on your own research goals and topic.
Blogs have become an increasingly reliable source of information and opinion over the last few years. Although anyone can start a blog, you can evaluate a blogger’s credibility by examining their biographical information and reading their posts for tone and perspective. The most credible bloggers will routinely refer to other sources. Their credentials will include formal education and affiliations with major institutions. Most likely, they’ll have published in other venues, not just their own website. Blogging platforms with the most traffic include Medium, WordPress, and Substack.
Newspapers and magazines are probably the most common secondary sources. They might release print editions, but almost all of them publish their content online now. They might publish on a daily, weekly, or monthly basis. They also tend to update their sites in real time as their staff finish writing and editing pieces. You can trust these sources because they have large staffs of professionally trained writers and journalists, and they’re overseen by editors and fact-checkers who assure the quality and accuracy of their information. These types of sources publish headline news, but also deeper analytical stories and op-ed pieces. They might present bias or political leanings, but they’re otherwise trustworthy sources of information. Some are more reliable than others, and you can use information literacy skills to determine how much you want to rely on them.
Academic journals are a mainstay of secondary sources. They include journals in the humanities, sciences, social sciences, medicine, economics, and other fields. You can trust these sources the most because they’re run by universities and nonprofit organizations. They only publish experts in their fields, and their research undergo rigorous peer review before publication. Academic researchers also must adhere to professional and ethical standards set by a variety of overseeing bodies, like institutional review boards. If an academic researcher violates these standards, they face severe consequences and generally cannot continue publishing.
You can find secondary source information in nonfiction books, which often blend primary forms of information. For example, a book like Jessica Bruder’s Nomadland provides a firsthand account of living with camper communities while working inside Amazon fulfillment centers. Bruder discusses her experiences with help from secondary sources that include other books, as well as newspaper and magazine articles. You in turn could wind up citing her book in a paper on Amazon’s working conditions.
There are hundreds of newspapers, magazines, and academic journals operating throughout the world. University libraries house the most reliable ones, and you can access them through databases like ProQuest, Academic Search Complete, Project Muse, JSTOR.
Tertiary Sources
Tertiary sources often serve as references to primary and secondary sources. These include bibliographies, lists, encyclopedias, and source guides. Anytime you come across a list of sources, you’re dealing with a tertiary sources. You might not use many bibliographies today, but odds are you’ll use lists and feeds that aggregate newspapers, magazines, blogs, and podcasts. One of the most common tertiary sources is Wikipedia.
Researchers use tertiary sources for a range of reasons. They serve as helpful starting points for research. Reference guides and encyclopedias help to create a comprehensive portrait of a topic, especially its history and the major talking points or debates. You wouldn’t cite a tertiary source, but you would use its sources as guide posts for mapping out your research project and thinking about what other sources to gather.
The Research Ecosystem
All of these sources live in an ecosystem, which means they often draw from and rely on each other. Newspapers and magazines use the primary information put together by agencies and institutions. They also report on findings from academic studies, and review nonfiction and academic books. Academic researches often reference newspaper and magazine articles in their studies, and they use statistics to help contextualize their own original data. When you do your own research, you’ll want to use a blend of these sources in order to gain a full, nuanced view on your topic.