Sandra--
I have a Barbara Louder in Wisconsin back in the mid 19th C, German lady, in
my roots. FYI.
You're right about census takers. I had a couple with all grown children who
listed them as if they all lived with them, even though many of the kids were
listed separately in their own residences. I researched the name Rifenbark
and found maybe twenty varieties of the name, many originating from the
imaginations of upstate NY census takers.
To be sure, the last name can be a real clue, say when the name is Karr. Carr
can be an original, but also a change. I don't find that people change from
Carr to Kerr, only the reverse, and usually a generation after immigrating to
US. I had Kerr in Scotland and they changed it to Carr when they moved to
London after being booted out of their homeland. Some Karr and Gehr also
changed to Carr in the US after a generation or two.