[DDI-SRG] FW: stats question please

[Wendy Thomas]

Different sets of statistics are easy as you can simply provide multiple 
summary statistics for the same variable. The question is when you use 
multiple weights to create a statistics. I recommended the use of a 
variable that reflects the generated weight using a generation instruction 
to describe the process. Then that weight can be referred to from the 
summary statistics. Did you have another approach??

wendy


On Tue, 24 Mar 2009, arofan.gregory wrote:

> Wendy:
>
> We're here in Ottowa working with the Canadian RDC people (Stats Can data)
> and they have exactly the same issue - they need to have different weights
> for a single study, and therefore different sets of statistics.
>
> This is *very* common in Stats Canada data, apparently.
>
> I'm happy to show you how I think it could be fixed.
>
> Cheers,
>
> Arofan
>
> -----Original Message-----
> From: ddi-srg-bounces at icpsr.umich.edu
> [mailto:ddi-srg-bounces at icpsr.umich.edu] On Behalf Of Wendy Thomas
> Sent: Monday, March 23, 2009 11:26 AM
> To: Sanda Ionescu
> Cc: Mary Vardigan; TIC list
> Subject: Re: [DDI-SRG] FW: stats question please
>
> We require the ability to make this machine actionable. We are creating
> variable representations of measures, concatonated measures providing
> unique identifiers and links. We are no longer just documenting data.
>
> Wendy
>
>
> On Mon, 23 Mar 2009, Sanda Ionescu wrote:
>
>> Wendy,
>>
>> It is for case 2) - a combination of weights.
>> But ... I don't know...
>> Creating a "fake" weight in DDI only (not in the data) seems a little
> far-fetched.
>> And really, I'm not sure we should be going that way.
>> Aren't we just documenting data?
>> Why resort to creating artifices like that - assigning fake values,
> creating imaginary weights?
>> And again, I think this makes it so much more difficult to automate - both
> direct markup, and conversions.
>>
>> Sanda.
>>
>> Sanda Ionescu
>> ICPSR
>> University of Michigan
>> P.O. Box 1248
>> Ann Arbor, MI 48106
>>
>> Phone, Fax: 734-615-7890
>>
>> -----Original Message-----
>> From: Wendy Thomas [mailto:wlt at pop.umn.edu]
>> Sent: Monday, March 23, 2009 12:48 PM
>> To: Sanda Ionescu
>> Subject: Re: FW: stats question please
>>
>> Please clarify
>>
>> If they mean that a variable can have more than one weight, a separate
>> statistic is created for each weight used.
>>
>> If they mean they use a combination of weights, then DDI 3.0 requires they
>> create a variable (not expressed in the data set physical content) that
>> provides the expression of that multiple weighting through its generation
>> instruction.
>>
>> For example: If I had a standard weight A and also applied weight variable
>> X and weight variable Y in calculating the statistic then I would need to
>> create a variable Z which using the generation instruction  of
>> "StandardWeightA * variableX * variableY.
>>
>> It may not be how they want to express it, but this is the way its done.
>>
>> Wendy
>>
>>
>>  On Mon, 23 Mar 2009, Sanda Ionescu wrote:
>>
>>> Hi, Wendy.
>>> This is a different issue.
>>> Our researchers/ analysis specialists seem to think that it is necessary
> to be able to reference multiple weights for a statistic.
>>> Please see exchange below.
>>> Could you submit this as a request for a change to TIC?
>>> Thanks
>>> Sanda.
>>>
>>> Sanda Ionescu
>>> ICPSR
>>> University of Michigan
>>> P.O. Box 1248
>>> Ann Arbor, MI 48106
>>>
>>> Phone, Fax: 734-615-7890
>>>
>>> -----Original Message-----
>>> From: Felicia LeClere
>>> Sent: Monday, March 23, 2009 10:14 AM
>>> To: Sanda Ionescu
>>> Subject: Re: stats question please
>>>
>>> It happens...so it is necessary to be able to have more than one weight
>>>
>>> -----Original Message-----
>>> From: Sanda Ionescu
>>> To: Lynette Hoelter; Felicia LeClere
>>> CC: Mary Vardigan
>>> Sent: Mon Mar 23 09:23:52 2009
>>> Subject: RE: stats question please
>>>
>>> It's about DDI.
>>>
>>> Version 3 only allows 1 weight to be defined per statistical value.
>>>
>>> And we need to know if it is necessary to ask for the weight to become
> repeatable (so that one can link to more than one).
>>>
>>> This is not about whether it's LIKELY or not (because, yes, it is
> UNLIKELY) but rather is it necessary to cover for that possibility too,
> however unlikely it may be?
>>> Sanda.
>>>
>>>
>>>
>>> Sanda Ionescu
>>> ICPSR
>>> University of Michigan
>>> P.O. Box 1248
>>> Ann Arbor, MI 48106
>>>
>>> Phone, Fax: 734-615-7890
>>>
>>> From: Lynette Hoelter
>>> Sent: Friday, March 20, 2009 4:22 PM
>>> To: Sanda Ionescu; Felicia LeClere
>>> Cc: Mary Vardigan
>>> Subject: RE: stats question please
>>>
>>>
>>>
>>> In theory, I don't see why not because the weights just multiple the
> values for the cases by some fraction, so you could multiply by two.
>>> Why?
>>>
>>>
>>>
>>> ....................................................
>>> Lynette F. Hoelter, Ph.D.
>>> Dir., Instructional Resources & Development, ICPSR
>>> Institute for Social Research
>>> University of Michigan
>>>
>>>
>>>
>>> From: Sanda Ionescu
>>> Sent: Friday, March 20, 2009 3:13 PM
>>> To: Felicia LeClere; Lynette Hoelter
>>> Cc: Mary Vardigan
>>> Subject: stats question please
>>>
>>>
>>>
>>> Felicia, Lynette,
>>>
>>> In Variable Statistics is it POSSIBLE  to obtain ONE value (say, mean, or
> mode, etc.) by applying TWO different weights - not sequentially, but at the
> same time?
>>> Thanks
>>>
>>> Sanda.
>>>
>>>
>>>
>>> Sanda Ionescu
>>> ICPSR
>>> University of Michigan
>>> P.O. Box 1248
>>> Ann Arbor, MI 48106
>>>
>>> Phone, Fax: 734-615-7890
>>>
>>>
>>
>> Wendy L. Thomas                          Phone: +1 612.624.4389
>> Data Access Core Director		 Fax:   +1 612.626.8375
>> Minnesota Population Center              Email: wlt at pop.umn.edu
>> University of Minnesota
>> 50 Willey Hall
>> 225 19th Avenue South
>> Minneapolis, MN 55455
>>
>
> Wendy L. Thomas                          Phone: +1 612.624.4389
> Data Access Core Director		 Fax:   +1 612.626.8375
> Minnesota Population Center              Email: wlt at pop.umn.edu
> University of Minnesota
> 50 Willey Hall
> 225 19th Avenue South
> Minneapolis, MN 55455
>

Wendy L. Thomas                          Phone: +1 612.624.4389
Data Access Core Director		 Fax:   +1 612.626.8375
Minnesota Population Center              Email: wlt at pop.umn.edu
University of Minnesota
50 Willey Hall
225 19th Avenue South
Minneapolis, MN 55455