A GENERATION -- how many years
Wilf Ratzburg
Is there a recognized way to calculating the length of a generation? I
would surmise that it is 20 or 25 years. Am I close?
Another question: This may sound peculiar, but I'd like to know what
"rule-of-thumb" one might use to calculate approximately how many
children would result from a generation. In other words, how could I
calculate approximately how many descendents one might expect after
"x" generations.
Cheers,
Wilf Ratzburg
frtz...@bcit.bc.ca
Jens Finderup Nielsen
It depends. I find that it averages out at about 30 years or 3 generations
per century.
As to number of children, that depends very much on when and where,
and how you define children. Is it children born or children surviving to
produce the next generation.
----------
% Fra: Wilf Ratzburg <frtz...@bcit.bc.ca>
% Til: gen-...@rootsweb.com
% Emne: A GENERATION -- how many years
% Dato: Thursday, November 13, 1997 5:05 AM
%
% Is there a recognized way to calculating the length of a generation? I
% would surmise that it is 20 or 25 years. Am I close?
%
%
% Another question: This may sound peculiar, but I'd like to know what
% "rule-of-thumb" one might use to calculate approximately how many
% children would result from a generation.
Jim Eggert
frtz...@bcit.bc.ca (Wilf Ratzburg) writes:
> Is there a recognized way to calculating the length of a generation? I
> would surmise that it is 20 or 25 years. Am I close?
In my database, the average age difference between a father and his
child is 33 years. Between a mother and her child the average is 29
years. (Each average considers over 4000 children spread over six
centuries, but mostly in the 19th and 20th centuries.) There is no
statistically significant difference in parents' ages between male and
female children in my data, nor would I expect one.
So I'd say a rule of thumb is 30 years for a generation.
Your mileage may vary.
--
=Jim Eggert Egg...@LL.mit.edu
Christian Vieser
Wilf Ratzburg <frtz...@bcit.bc.ca> wrote:
: Is there a recognized way to calculating the length of a generation? I
: would surmise that it is 20 or 25 years. Am I close?
Of course there has always been couples marriaging early or lately. But the
average does depend on the time frame, region and social status of persons.
So it's hard to calculate who many generations there are in, say, 200 years.
It can be 10, it can be 6. Today most couples marry in an age near thirty
their first time, in 1800 the common age for marrying was about twenty.
: Another question: This may sound peculiar, but I'd like to know what
: "rule-of-thumb" one might use to calculate approximately how many
: children would result from a generation. In other words, how could I
: calculate approximately how many descendents one might expect after
: "x" generations.
Same problems: the number of children haevily depends on time frame and
social status. Some couples didn't have children at all, some had a dozend.
If I took my database and would calculate an average on the number of children,
you can't figure out the number of descendents after "x" generations,
because so many children died before the age of marriage.
So, if you take a big database, you can calculate an average. But the variety
is so big, that you can't expect your ancestry developed in a similar way.
Regards,
Christian Vieser
RayNicklas
>In my database, the average age difference between a father and his
>child is 33 years. Between a mother and her child the average is 29
>years. (Each average considers over 4000 children spread over six
>centuries, but mostly in the 19th and 20th centuries.) There is no
>statistically significant difference in parents' ages between male and
>female children in my data, nor would I expect one.
>
>
Glad to hear a statistical sampling that verifies what I've been using.
I'd heard, and therefore used, 30 years as a generation, and it seems to
fit my own data. Many people get confused about the age of marriage, but
that only sets the lower limit of the distribution. I usually look at the
range of child-birth years, find a median, then stab just lessthan 30 for
the mother's birth, and just more than thirty for the father's.
Thanks for the verification.
Ray
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