I like to use the GEDCOM qualifiers to remind myself of the nature of the
approximated birth year.
I use "calculated" when the date has been generated by a calculation
(back-calculated from a year in a census record).
I use "estimated" when I have made some guess of my own (and record the
reasoning in a research note).
The real challenge comes when forms such as the US WWI and WWII Draft
Registrations, which have both a date of birth and an age on them, are not
consistent with each other! In those cases, I've found that the day and
month are often accurate, but the year of birth has been reported wrongly
or calculated from the age.
One of the people in my database has a WWII reg card that put his birth in
1892, and as far as I've been able to tell, he was baptized in 1890! All
of the records with dates agree that he was born in July, and those that do
have a day recorded agree on the day, but the year is all over the place.
On Fri, Dec 25, 2015 at 9:32 AM, Paul via <
Here are some more thoughts about recording birth dates.
Perhaps most of the time, you will have several "data points" that imply
birth year - for example one (or probably more) census age, possibly age at
marriage, even age at death.
In the absence of a definite DoB (usually from birth certificate), the
"real" date will likely have an uncertainty of *at least* a year.
This is because census age reporting is notoriously variable, and even age
at death may well not be accurate.
(Incidentally, it is not unknown for claimed birth dates on a certificate
be in error - deliberately or not.)
My own approach is to choose a birth year that best fits the available data
and qualify it with "App(roximate)".
Note that the Family Historian Property Box Event display is very handy
in highlighting which event ages are "out of bounds".
Note also that I try to avoid a birth date range expression like "Between x
And y" because FH cannot then do its date calculations!
I don't know how widely this is understood, but apparently FH treats
or "c.1870" as "1 Jan 1870" for calculation purposes.
Similarly "Feb 1870" would be taken as "1 Feb 1870" and "Q3
1870" as "1 Jul
The important things are to be consistent about your method of recording
birth date *and* to include reported age in your source citations (so
can form their own opinion).
Just a couple of extra comments.
There is not *usually*, in my opinion, much point in trying to estimate
birth date to better than a year (some life event ages may be
However, with a birth registration index you may be able to narrow that
to a specific quarter (e.g. Q3 1870).
In that case I would choose the birth date as "c. Aug 1870".
Note that I chose *middle* month of the period on the basis that the actual
*registration* date would be at most about one month in error.
And in all but exceptional cases the actual birth date would not have been
more than a week or two different from that.
Happy Christmas, All
P.S. I did not mention the other two GEDCOM date qualifiers "Calculated"
This is not the place to resurrect discussion about the differences from
Suffice to say I get by perfectly well without them. except in some very
To unsubscribe from the list, please send an email to
FAMILY-HISTORIAN-USERS-request(a)rootsweb.com with the word 'unsubscribe'
without the quotes in the subject and the body of the message