The Value and the Risk
When doing family histories, many people rely on information passed down to them from older generations. This can be a good thing, even a very invaluable thing! Sometimes, we would never know something had it not been for oral information.
At other times, oral information is risky. Oral information often has a grain of truth to it, but other layers of misinformation are often built on top of the truth. We can barely relay, with 100% accuracy, what we just heard yesterday from someone else. Can you imagine trying to keep information accurate that is 100 years old, by using our memories alone?
Passing down information orally is necessarily limited by people's understanding, or lack thereof. Sometimes an older informant had an opinion, but by the time it gets to the grandchild, opinion has turned into fact. And lastly, some people are not above making things up, which make the person or the family look better than what s/he is or they are.
A case where oral tradition and documented fact blended well
Many years ago, an elderly grand aunt told me the name of one of my ancestors. She only knew it from what she heard when she was a child, and retained it in her memory. She wasn't even sure of the spelling or precise name. Then, some years later, I came across an original document, not even looking for it, which had the very name she said. The document proved that the person truly existed. Later, I found dozens of other original documents, spanning many years, with that person's signature. The proof became more convincing.
A case where oral tradition and documented fact collided
But in another case, I was told that so-and-so was born here or there. That was the family's belief for generations. Then I came across the actual baptismal record of the person. It contradicted the family legend. Now, it is also important to know that documents and records are not always fool-proof. Records are written by human beings, who sometimes make mistakes or record things wrongly on purpose. But, in this case, I had other evidence that validated the baptismal record. The family still hung on, though, to what they believed all these years. And it is understandable if they did so.
My basic principle in history is : MAYBE, MAYBE, MAYBE. Proof is so hard to find with our local history, and oral tradition has its value, but also its limitations.