College writing assignments generally ask you to respond in some way to sources. Some assignments will require you to consult only sources assigned in class, while others will require you to locate your own sources relevant to a specific research topic. In many of your courses, your research will focus primarily on written texts such as books and scholarly articles, but you may also be asked to consult a variety of other sources, including letters, diaries, films, works of art, data from experiments, numerical data, surveys, and transcripts of interviews.
What constitutes a useful and reliable source will vary according to both your assignment and the methods used in a particular field of study. As you approach a paper in an unfamiliar field, it will be important to remember that within each field of study, scholars distinguish between primary sources, or the raw material that they analyze as they attempt to answer a question, and secondary sources, or the analyses of that raw material done by other scholars in the field. For example, for literary scholars, primary sources include fiction and poetry, while secondary sources include criticism written by other scholars about those literary texts. Historians, on the other hand, grapple with primary sources such as letters, diaries, and eyewitness accounts produced at the time of an event, as well as with secondary sources such as arguments presented by other historians. Sociologists tend to rely for raw material on quantitative data, such as surveys, censuses, and other statistics, or qualitative data, such as observation and interviews.
Social scientists in some fields, such as psychology and economics, also consider empirical journal articles (articles that describe the results of original research) published in peer-reviewed journals to be primary sources. These articles provide raw material for other scholars, who may then raise questions about the published results or develop new research based on these results. Social scientists in other fields, such as anthropology and history, however, do not consider research articles primary sources because articles in these fields do not typically present raw data. For these social scientists, journal articles would be secondary sources. For all social scientists, literature reviews and published books are considered secondary sources.
Natural scientists consider empirical articles published in peer-reviewed journals to be primary sources. These published results of experiments and analyses of data provide the raw material for other scientists to consider as they pursue their own research. Secondary sources in the natural sciences include literature reviews and books.
As a college student taking courses in many different fields, you will need to ask questions about what is considered a reliable source in each new field, and about how sources can be used appropriately in that field. At the same time, there are many common principles for using sources effectively that you will be able to carry with you from course to course. For more information on using sources in different disciplines, you can consult the Harvard Writing Project series of writing guides for specific courses and concentrations. If you are writing a paper for a course in the Government department, you should consult GovWrites for guidance. If you are writing for an anthropology course, you should consult AnthroWrites. If you are writing for a course in one of the Life Sciences fields, you should consult ScienceWrites.
When in doubt, of course, you should always consult your instructor.