I am researching a relative born in Rakov (today's Belarus, then in Russian
Pale, between Minsk and Vilna). In American documents I have seen her birth
date given as 1886; I am aware that the old style calendar was in use in
Russia at that time.

My question is: is it likely that this date, which presumably my relative
used on documents after emigrating, is the old style -- or is it likely that
she (or some American official) re-calculated her birth year to the new style
calendar after she emigrated to the US in 1905?

David Laskin