Message/Author 


Dear Dr. Muthèn: I have to compute a latent variable (ABS – affective balance score) that represents the latent difference of two latent variables (PA – positive affect and NA negative affect). Then I need to regress the obtained latent score (ABS) on another latent variable (IQ). I have heard of computing latent difference score which should be NA = PA@1 and then computing NA on IQ – where NA represents now the ABS. Is that syntax correct? OR do you have other suggestions how to best compute the difference of two latent variables? Thank you MODEL: IQ by IQ_VB IQ_RA IQ_VI IQ_SP; NA by Q_NA_1_2 Q_NA_2_2 Q_NA_3_2; PA by Q_PA_1_2 Q_PA_2_2 Q_PA_3_2; NA on PA@1; NA on IQ; 


Remove: NA on PA@1; NA on IQ; Try: diff BY; diff ON pa@1 na@1; diff@0; 

Jiawen Chen posted on Tuesday, August 26, 2014  4:04 pm



Dear Dr. Muthèn: I wonder if I can model the latent difference score of two different variables because so far all I have come across is about modeling latent difference score of the same variable across different waves. I have a variable called intrinsic work values, measured by three items: "if you are to look for a fulltime job, how important are the following job characteristics (5 point scale): a)job is interesting; b)I make most of the decisions; c)I feel accomplished." I have another variable called intrinsic work rewards, measured by exactly the same items, only the question was asked differently, "describe how strongly you agree with the following characteristics about your current job (5 point scale)." So if I want to study how the discrepancy between work values and rewards predicts a host of outcome variables, is it appropriate to model the latent difference score between them at the same wave? Can I also do a thirdorder latent growth model of the latent difference score across multiple waves? Or some other method may be more suitable for what I want to study? Thank you very much! 


It seems to me that one can do some version of latent difference modeling also with different variables, but I haven't tried. 

Lixin Jiang posted on Wednesday, September 03, 2014  9:07 pm



I have two time points measures (NSsad, SSsad), which have been counterbalanced in my study. Now I want to use gender and personality trait to predict this latent change. See below that I have used it as latent growth model. However, it seems to be misleading as it is not growth itself. How do I model this "latent difference/change score model"? Thanks. i sNSsad@0 SSsad@1; s on sex CA; NFSAD(1); SFSAD(1); 


A linear growth model cannot be identified with only two time points. I would instead create a change score as follows: f BY nssad@1 sssad@1; f ON sex ca; 

Roger Brown posted on Thursday, September 04, 2014  9:39 am



I worked up this simple difference test with a covariate the other day and checked it against a group test on a difference vector. Is this what you are thinking of? title: LCS used to estimate paried ttest with covariate data: file is ttest.txt; variable: names are x y1 y2; model: lcs on y1@0; lcs by y2@1; y2 on lcs@1; y2 on y1@1; y2@0; lcs on x; 


Shouldn't there be a negative sign somewhere? 

Lixin Jiang posted on Thursday, September 04, 2014  4:21 pm



Thank you, Roger. The results based on your codes were more consistent with the regression results from SPSS. 

Back to top 