Primary Source Documents: Someone who is the “first person” creates primary sources; these documents can also be called “original source documents.” The author or creator is presenting original materials as a result of discovery or to share new information or opinions. Others have not filtered primary documents through interpretation or evaluation. In order to get a complete picture of an event or era, it is necessary to consult multiple—and often contradictory—sources (i.e., letters, journals, interviews, speeches, photos, paintings, etc.). Research studies written by the researchers who conducted the study are primary sources in the sciences.
Secondary Source Documents: Materials that are produced with the benefit of hindsight and materials that filter primary sources through interpretation or evaluation. Books commenting on a historical incident in history are secondary sources. Political cartoons can be tricky because they can be considered either primary or secondary. Articles, books, or other documents discussing research that was not conducted by the writer(s) are secondary sources in the sciences.