Whether conducting research in the social sciences (especially history), humanities, arts, or natural sciences, the ability to distinguish between primary and secondary source material is essential. Basically, this distinction describes the degree to which the author of a piece is removed from the actual event being described. Is the author reporting impressions first hand from personal experience, or is the author conveying the experiences and opinions of others—that is, second hand?
These are contemporary accounts of an event, written by someone who experienced or witnessed the event in question. These original documents include diaries, letters, memoirs, journals, speeches, manuscripts, interviews and other such unpublished works. They may also include published pieces such as newspaper or magazine articles (as long as they are written soon after the fact and not as historical accounts), photographs, audio or video recordings, research reports in the natural or social sciences, or original literary or theatrical works. They are not documents that discuss or evaluate other documents or publications about the event.
The function of secondary sources is to interpret primary sources, so they can be described as at least one step removed from the event or phenomenon under review. Secondary source materials, then, interpret, assign value to, speculate upon, and draw conclusions about the events reported in primary sources. Secondary sources are usually in the form of published works such as journal articles or books, but may include radio or television documentaries, or conference proceedings.
When evaluating primary or secondary sources, the following questions might be asked to help ascertain the nature and value of material being considered:
Ultimately, all source materials no matter what type must be assessed critically, and all works describe events as scene through the eyes of the writer/interpreter. This must be taken into account when one is attempting to arrive at the 'truth' of an event.