Casefile Clues

07 July 2011

Percents and Genealogy

One often sees comments like these made on various blogs, mailing lists, etc.

X% of children were not born of the father.

X% of families followed the pattern of naming the first born child after the paternal grandfather.

I've never found statements like these particularly helpful from a genealogical standpoint.

One reason is that often these statements are made without reference to any study in which they were "discovered" or what analysis was done to reach the conclusion regarding why the percentage is accurate, etc. The source of the statement is often one missing element in these posts. Numbers without data to back them up are truly meaningless.

Even if there is a study to back up the number, one always has to wonder how the study was conducted, how samples were obtained, how random the samples actually were, how representative of the entire population the extracted items were, etc. etc. Is the study really applicable to my research, the family I am working on? Were certain records used that inherently have some bias or tend to only mention members of a certain socio-economic group? That always makes me wonder how applicable the percentage is to my research.

And therein lies the real problem.

Let's say that 75% of families from a certain ethnic background name the oldest son for the paternal grandfather and that this statement comes from a repeatable study that is done using sound research practices. What does that mean for me and my research? It means that I can use the oldest child's name as a clue as to who the paternal grandfather is. That's it. It is not proof. And frankly it really doesn't matter from the standpoint of my research whether the percentage is 60%, 80% or 95%. I can use the fact that there is a tendency to possibly guide my research, but personally in most cases, I'm better off using local records and sources to guide my research.

And rarely does anyone who makes claims provide any documentation of where the number comes from. What about the citation of sources in regards to numbers as well as genealogical facts?

I really do not understand why people are extremely interested in these numbers anyway. Statistics are intended to help us see general patterns or trends for groups as a whole. Genealogy is about proving what happened in specific instances.