proportions as DVs

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proportions as DVs

Maguin, Eugene

Do any of the more recent spss routines offer a better method for analyzing proportions than what I understand to be the traditional method of applying some type of transformation (arcsine, logit, probit) to the DV to stabilize the variance? Let me give a specific example: Data: random samples of students in schools (ignore weighting). Student level DV is post high school education attainment scored as five categories. Analysis is at the school level. Thus a DV is proportion of students in a category.

 

Thanks, Gene Maguin

 

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Re: proportions as DVs

Jon K Peck
The logit translation is often a good choice.  There is also an extension command named STATS PROPOR REGR that estimates the proportion equation directly.  See the SPSS Community (www.ibm.com/developerworks/spssdevcentral) Extension commands collection.


Jon Peck (no "h") aka Kim
Senior Software Engineer, IBM
[hidden email]
phone: 720-342-5621




From:        "Maguin, Eugene" <[hidden email]>
To:        [hidden email],
Date:        01/21/2014 02:25 PM
Subject:        [SPSSX-L] proportions as DVs
Sent by:        "SPSSX(r) Discussion" <[hidden email]>




Do any of the more recent spss routines offer a better method for analyzing proportions than what I understand to be the traditional method of applying some type of transformation (arcsine, logit, probit) to the DV to stabilize the variance? Let me give a specific example: Data: random samples of students in schools (ignore weighting). Student level DV is post high school education attainment scored as five categories. Analysis is at the school level. Thus a DV is proportion of students in a category.
 
Thanks, Gene Maguin
 
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Re: proportions as DVs

Bruce Weaver
Administrator
In reply to this post by Maguin, Eugene
Hi Gene.  I suppose your 5 attainment score categories are ordinal, are they?

I know you say analysis is at the school level, but do you have the student level data?  If you do, I suspect you could get a suitable model via GENLINMIXED.  Here are a couple of examples from the FM:

(Nominal) Multinomial logistic regression

GENLINMIXED
  /FIELDS TARGET=bfast
  /TARGET_OPTIONS DISTRIBUTION=MULTINOMIAL LINK=LOGIT
  /FIXED EFFECTS=agecat gender active.

(Ordinal) Multinomial logistic regression

GENLINMIXED
  /FIELDS TARGET=chist
  /TARGET_OPTIONS DISTRIBUTION=MULTINOMIAL LINK=CLOGLOG
  /FIXED EFFECTS=numcred othnstal housng age duration.

Of course, you could add school-level explanatory variables and random effects, etc.

HTH.


Maguin, Eugene wrote
Do any of the more recent spss routines offer a better method for analyzing proportions than what I understand to be the traditional method of applying some type of transformation (arcsine, logit, probit) to the DV to stabilize the variance? Let me give a specific example: Data: random samples of students in schools (ignore weighting). Student level DV is post high school education attainment scored as five categories. Analysis is at the school level. Thus a DV is proportion of students in a category.

Thanks, Gene Maguin
--
Bruce Weaver
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Re: proportions as DVs

Maguin, Eugene
Yes, they are ordinal but I don't know that they would meet the proportional odds assumption for ordinal regression. I'm looking at the Genlinmixed documentation now but I don't see anything to indicate that that could be tested as it can in Plum. We do have student level data but the analysis is to use school level variables such as free lunch percentage, percent minority, teacher FTE per student, etc. The school level IVs are not aggregated student variables. Thus it's really a multilevel analysis and my impression, quite possibly wrong, is that Genlinmixed can't do a multilevel analysis comparable to Mixed.

Jon (thank you) suggested a logit transform and we can do that in spss. I'm not so sure about this but I also think that we can use GLM as a multivariate regression routine.
Gene

-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of Bruce Weaver
Sent: Tuesday, January 21, 2014 5:12 PM
To: [hidden email]
Subject: Re: proportions as DVs

Hi Gene.  I suppose your 5 attainment score categories are ordinal, are they?

I know you say analysis is at the school level, but do you have the student level data?  If you do, I suspect you could get a suitable model via GENLINMIXED.  Here are a couple of examples from the FM:

*(Nominal) Multinomial logistic regression*

GENLINMIXED
  /FIELDS TARGET=bfast
  /TARGET_OPTIONS DISTRIBUTION=MULTINOMIAL LINK=LOGIT
  /FIXED EFFECTS=agecat gender active.

*(Ordinal) Multinomial logistic regression*

GENLINMIXED
  /FIELDS TARGET=chist
  /TARGET_OPTIONS DISTRIBUTION=MULTINOMIAL LINK=CLOGLOG
  /FIXED EFFECTS=numcred othnstal housng age duration.

Of course, you could add school-level explanatory variables and random effects, etc.

HTH.



Maguin, Eugene wrote
> Do any of the more recent spss routines offer a better method for
> analyzing proportions than what I understand to be the traditional
> method of applying some type of transformation (arcsine, logit,
> probit) to the DV to stabilize the variance? Let me give a specific
> example: Data: random samples of students in schools (ignore
> weighting). Student level DV is post high school education attainment
> scored as five categories. Analysis is at the school level. Thus a DV is proportion of students in a category.
>
> Thanks, Gene Maguin





-----
--
Bruce Weaver
[hidden email]
http://sites.google.com/a/lakeheadu.ca/bweaver/

"When all else fails, RTFM."

NOTE: My Hotmail account is not monitored regularly.
To send me an e-mail, please use the address shown above.

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