I just had someone ask me a crucial question: “Isn’t that a reliable source?”
There aren’t easy yes and nos.
There are few ways we measure reliability in genealogy.
1) Is it an original or derivative source? An original source is an item in its original form. Think a marriage record as it was first written down. A derivativesource has been changed in some way. Think about looking at an index.
Why does it matter? Can you always read the handwriting of a doctor’s prescription? People make mistakes when they recopy. Handwriting issues are one of the biggest issues.
2) Is it primary or secondary information? Information is the material contained within the source. For a birth record, that could be the baby’s birthdate, the parents’ names, etc. Primaryinformation is coming from someone who is aware and present at the event. You know your own occupation Secondary information is coming from someone who has heard it elsewhere. Do you know your great-great-grandparents’ occupations from first hand experience?
3) Is indirect or direct evidence? Evidence is how you use the information to answer the question. Direct evidence answers the question without further work. For example, a marriage certificate will list the marriage date. Indirect evidence requires further work. For example, a gravestone which lists a death date and age at death will help you determine when someone was born but will not give you the exact date.
A few other things to think about when looking at genealogies: do you know where the information came from? I always measure the strength of a genealogy by the number of sources cited. That means the writer is getting their evidence from original sources instead of great-grandfather’s possibly faulty memory. Second, do you know what their motivation was? Someone attempting to trace a whole town might not be as thorough as someone just working on your family.