Wednesday, March 01, 2006

Re: st: counting number of children in a household

On 3/1/06, Austin Nichols <austinnichols@gmail.com> wrote:

> As for the claim due to Neil Shephard <nshephard@gmail.com> that > "A further problem with this is that it also assumes that children are > literally that, ie. they are considered to be legally considered as > children." > Well. Hmm. It is a problem defining children as children? > > If Scott Cunningham <scunning@gmail.com> had wanted to count > biological children, he would have said so, and it would not make > sense to count them at the household level, probably. "In the field > of human genetics" would you count adopted children or only offspring > when answering Scott's question? > > Now foster children, counting kids at the family level, that's tricky.

Apologies for the lack of clarity, in human genetics because the interest is in heritable factors adopted children are of little interest since they do not share any genetic material with the individuals who have adopted them.*

I confess I did not go back and read the original posting from six days ago which made the assumption that children are those aged < 19, and can only apologise for that. But there may be instances where there are children >= 19 living at home, or grandparents living with their off-spring, so would you then count their offspring (the parents) as children? This is what prompted my posting, althoug had I been more fastidious and returned to the original posting (which I had not seen on the list) then I would not have made any posting.

The FAQ referenced (which I was totally unaware of and have now read, and I thank you for bringing it to my attention) is very useful and the structure described is very similar to that which is widely used in human genetics which is descibed in chapter 2.7 at...

http://linkage.rockefeller.edu/soft/linkage/

and also at...

http://www.sph.umich.edu/csg/abecasis/Merlin/tour/input_files.html

(This stems from the structure used in the first program written to handle pedigree data, LIPED, which came out in 1976 and was written by Jurg Ott).

The main difference between the two structures is that in the LINKAGE format there are never any missing parental identifiers, they are assigned ID's, and sexes even if there is no actual data, as you still need to know who the founders are from which the genetic markers will have been inherited and which you are attempting to trace through the pedigree.

I apologise for the inappropriate intrusion on the thread, and shall remember in the future to read the original posting prior to posting in the future.

Must get back to work now,

Neil

* Interestingly you do come across instances where people have volunteered to participate in family studies, and have had the reasoning explained to them but still volunteer to participate (themselves and their 'off-spring'), and after genotyping it is clear that the 'off-spring' are not related to the parents, this may be because they have not informed the adopted child. Even more intersting is that you occasinally come across instances of non-parentage, where its clear that the biological mother is indeed the biological mother, but the father has clearly not sired the off-spring, it may have been the 'milkman'. Obviously confidentiality prevents researchers from knowing the true identity of people enrolled in studies as identifiers are used instead of names and under the ethics of such studies information is not allowed to be passed back to the participants.

-- "There is always an easy solution to every...problem - neat, plausible, and wrong." - H. L. Mencken

Email - nshephard@gmail.com / neilshep@cyllene.uwa.edu.au Website - http://slack.ser.man.ac.uk/ Blog - http://slack---line.blogspot.com/ Flickr - http://www.flickr.com/photos/slackline/

* * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/


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