[DDI-users] Group vs Universe
My Coyne
mcoyne at boninc.com
Thu Jan 27 14:57:04 EST 2011
Hi DDI Community,
After reading and viewing the xsd for group and universe concepts, I find that I don't have a clear view of the these two
concepts. Would someone please give me a better understand of both of these in comparison.
1. I understand that group is used to group StudyUnits and subgroups (assuming that subgroups are not study units)
-- Grouping factors (differentiators) can be: time, instrument, panel, geography, datasets, language
2. I understand that Universe is an attribute of StudyUnits
I would like to present a fictitious scenario in helping me solidifying the concepts.
StudyUnit A
Universe A: all families of the USA
Timeframe: 1970 - 2010
In this study data collected are: marital status, education, incomes, geographical residence, religions, political affiliation for
both parents and children
StudyUnit B
Universe B: All families of the USA who have child/children diagnosed autistic within the spectrum
Timframe: 1990-2010
In this study similar data as in StudyUnit A are collected with additional information for autistic diagnosis and genotypes of
the children.
Using Grouping and/or Universe concepts, Could I then retrieve datasets that contains
(a) information that intersect of the two universes (of studyA and StudyB)
(b) information about the families that do not have autistic children
?
Thank you for your help.
I would like to retrieve two datasets D1: with all children of the USA
My Coyne
mcoyne at boninc.com
(cel): 301-399-6351
More information about the DDI-users
mailing list