Re: Binomial multivariate repeated GLM

Posted by torvon on
URL: http://spssx-discussion.165.s1.nabble.com/Binomial-multivariate-repeated-GLM-tp5721013p5721223.html

Alex, Bruce, Gene. 

Let's stick to the modeling of observed variables for now. I'll read up on ways to model this in MPLUS differently and might just report both analyses. 

I had the data coded in the "long long" format originally ("ID * time * symptoms" rows), the way you suggested it now. 

However, in the recommended post above (http://spssx-discussion.1045642.n5.nabble.com/Mixed-models-Repeated-Measures-multiple-DVs-SPSS-td5720624.html#a5720639) the data are set up differently: the variable x is used as pre-test DV, and the variable y as post-test DV. That's why I recoded accordingly to this syntax, and that's where the problems come from.

(1) Doing it as MIXED now with the long long format looks like this: 

MIXED symptoms BY time phq_index

  /FIXED=time phq_index time*phq_index | SSTYPE(3)

  /METHOD=REML

  /PRINT= g r SOLUTION

  /RANDOM=INTERCEPT | SUBJECT(UserID) COVTYPE(VC)

I added UserID as random intercept here, hope that makes sense. It gives me significant fixed effects "time" (because all symptoms increase), "symptoms" (because symptoms differ from each other?) and "index*time" (because symptoms change differentially over time). Correct interpretation and syntax?

(2) Doing it as GENLIN looks like this: 

GENLIN symptoms (ORDER=ASCENDING) BY time phq_index (ORDER=ASCENDING)

  /MODEL phq_index time time*phq_index DISTRIBUTION=MULTINOMIAL LINK=CUMLOGIT

  /PRINT CPS MODELINFO FIT SUMMARY SOLUTION.

The model finds the same significant effects. 

(3) Lastly, GENLINMIXED: 

GENLINMIXED

  /DATA_STRUCTURE SUBJECTS=UserID

  /FIELDS TARGET=symptoms

  /TARGET_OPTIONS DISTRIBUTION=MULTINOMIAL LINK=LOGIT

  /FIXED  EFFECTS=phq_index time phq_index*time USE_INTERCEPT=TRUE

  /RANDOM EFFECTS=UserID USE_INTERCEPT=TRUE SUBJECTS=UserID COVARIANCE_TYPE=VARIANCE_COMPONENTS 

  /BUILD_OPTIONS TARGET_CATEGORY_ORDER=ASCENDING INPUTS_CATEGORY_ORDER=ASCENDING MAX_ITERATIONS=100 

    CONFIDENCE_LEVEL=95 DF_METHOD=RESIDUAL COVB=MODEL.

Which just runs for an hour and then crashes SPSS. Tried it 3 times now. 

Thank you very much for your time & help!

 Eiko

 

On 16 July 2013 17:09, Alex Reutter [via SPSSX Discussion] <[hidden email]> wrote:

"
t0 = 9 DVs at time 0
t2 = 9 DVs at time 2
"

Stop right here.  MIXED and GENLINMIXED do not use the same data structure as GLM for repeated measures.  You need to use the Restructure Data Wizard (pasting VARSTOCASES in this situation).  There's an example of preparing a data file this way in http://pic.dhe.ibm.com/infocenter/spssstat/v21r0m0/topic/com.ibm.spss.statistics.cs/mixed_diet_intro.htm.

Alex




From:        torvon <[hidden email]>
To:        [hidden email],

Date:        07/16/2013 07:16 AM

Subject:        Re: Binomial multivariate repeated GLM
Sent by:        "SPSSX(r) Discussion" <[hidden email]>

---

In the link Bruce sent, I think random effects are being used to measure the effect of the repeated measurements.  That should also work with GENLINMIXED.  Can you send your current syntax to the list?

Alex

I decided to model this as MIXED first, and if it works and I know how to interpret it, I'll change it into GENLINXMIXED. 

To repeat my question: do 9 items change differentially over time. I have 2 time points, 9 DVs, and no intervention, and neither do I have schools or classes (but 1500 N). 

t0 = 9 DVs at time 0
t2 = 9 DVs at time 2
index = index coding the information about the 9 items

mixed t2 by index with t0
/fixed = index index*t2 | noint sstype(3)
/method = reml

/print = g r solution 

so far so good. 

Now, I don't exactly understand what these lines do: 

/random = index | subject(school_id) covtype(un) <<< I do not have schools
/repeated = index | subject(UserID) covtype(un).

If I simply use 

/random = index | subject(UserID) covtype(un)
/repeated = index | subject(UserID) covtype(un).

SPSS crashes ;) 

Thank you!
 Eiko












 

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