- Primary sources help us reverify information which has been published in secondary sources.
- Primary sources help us correct any errors which have been published in secondary sources, and which ironically have been reproduced several times to a point where subsequent secondary and tertiary sources keep publishing the error as a fact. For eg several sources attribute the film Prem Sagar to have been directed by K. SUBHRAMANYAM, where as the film was actually directed by Pandit Narottam Vyas. K. Subhramanyam’s flagship production company MUAC distributed the film.
- Primary sources help us find new information, that may not necessarily have interested those authors who have used them in the past. (eg Sailen Bose is today well recognized as a well known cinematographer. But primary records also show that he had a film processing lab which was contractually attached to the Motion Picture Studios).
- Primary sources provide dates which give us a more accurate perception of chronological events in a time line. Secondary sources typically do not mention dates, or provide a very vague timeline. Some of these dates also tend to be incorrect. For eg. Several sources cite the date of the fire accident at the motion picture studios to be 21 Dec 1940, but the actual date of the event was Dec 11, 1938.