I am trying to understand the generations matrix at Gedmatch. I am not sure I understand what is meant by the term "Most Recent Common Ancestor."

For example, if the MRCA for a match is said to be 4.0, does this mean that the test-taker and the match have a common great great grandparent or does it mean a common great grandparent?

You yourself are not your ancestor, so an MRCA of 4.0 would seem logically to refer to your great great grandparent. (your parents would be the first level of ancestors, therefore have an MRCA of 1, your grandparents an MRCA of 2, your great grandparents an MRCA of 3, and your great great grandparents an MRCA of 4)

However, it seems that Gedmatch counts the test-taker as the first generation of ancestor, so that an MRCA of 4.0 would indicate only your great grandparent. If that meaning is correct, then MRCA would be yourself = 1, your parents = 2, your grandparents = 3 and your great grandparents = 4.

I'm not trying to criticize the semantics, I just want to understand how to interpret what is being said. If I see the term MRCA = 4, is the common ancestor my great great grandparent or my great grandparent?

Thanks in advance.