[DDI-SRG] FW: stats question please

[Sanda Ionescu]

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