Re: Running MIXED with time as a factor

Posted by Poes, Matthew Joseph on Jun 07, 2012; 2:20pm
URL: http://spssx-discussion.165.s1.nabble.com/Running-MIXED-with-time-as-a-factor-tp5713561p5713567.html

I think you may be a bit confused on how to interpret the coefficients.  The 3rd category is in the model, it's just a redundant parameter.  All the information for getting the time 3 coefficient is in the model.  Let's look at it a bit more simply first.  If you had a model that only had time and nothing else.  Then time 3 would be the intercept value.  Now let's add in a gender variable.  If 1 is Boy, then the intercept is now the time 3 coefficient for girls.  If you believe growth is different for boys and girls, you would include an interaction for gender by time.  So how do you know the time 3 coefficient for boys.  It's the intercept plus the different for gender, plus the time coefficient plus the difference for gender of that.  Where is that coefficient, it's the interaction coefficient.

I know a lot of people will  calculate all the coefficients in something like excel to make this easier, and that is certainly something you could do.

Matthew J Poes
Research Data Specialist
Center for Prevention Research and Development
University of Illinois
510 Devonshire Dr.
Champaign, IL 61820
Phone: [phone]
email: [hidden email]


-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of kine
Sent: Thursday, June 07, 2012 9:00 AM
To: [hidden email]
Subject: Running MIXED with time as a factor

Dear subscribers,

I would like to get the parameter estimation on ALL the categories (time 1, time 2, time 3) in my three-way interaction analysis. As of now, SPSS only estimates time 1 and 2 (as it often does with categorical data).

How may I obtain this information? Please find present syntax below:

mixed Exlog with OPce Posce pssce pcsce Gender Age Sector Respons Tenure Hour_w BY time /CRITERIA=MXITER (5000) /print=solution
  /method=reml
  /fixed = Gender Age Sector Respons Tenure Hour_w OPce time OPce*time OPce*POSce OPce*PsSce OPce*PcSce PoSce pssce pcsce pssce*time pcsce*time Posce*time POSce*OPce*time PsSce*OPce*time PcSce*OPce*time
  /random intercept time | subject(id) covtype(VC).

Best regards,
Kine

--
View this message in context: http://spssx-discussion.1045642.n5.nabble.com/Running-MIXED-with-time-as-a-factor-tp5713561.html
Sent from the SPSSX Discussion mailing list archive at Nabble.com.

=====================
To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
SIGNOFF SPSSX-L
For a list of commands to manage subscriptions, send the command
INFO REFCARD