Sometimes you are faced with conflicting pieces of "evidence" for genealogical data. How do you determine which is more apt to be correct?
Here’s the guideline I use:
First hand information recorded at the time of the event carries more weight. For example, if a birth appears on a birth certificate, it is likely to be more accurate than a birth date recorded on a death certificate. The date on the death certificate was recorded long after the event occurred. That is not to say the date is incorrect on the death certificate; you just have to treat it with caution and be open to other sources of information.
In oral history, if the person telling the event was actually there when the event occured, it is more likely to be correct than if the event is being told by someone who was not there. Keep in mind, however, that the memories of all of us dim with the passing years.