Message/Author 

JM posted on Tuesday, May 26, 2009  12:58 pm



Hi, when examining longitudinal measurement invariance, comparing equal form, factor loading, and indicator intercept models, I understand that chisq diff testing is done to check as to whether the nested models differ compared to the comparison model; however, should I also be looking at estimates in the output to check for specific changes or nonchanges in standardized or understandarized (not sure which) coefficients? Thanks! 


I would look at modification indices. 

Sean Tucker posted on Wednesday, August 26, 2009  8:46 pm



Dear Linda, I have a three wave longitudinal dataset with equal time intervals. Following Chan (1998) I am trying to test for measurement invariance but I can’t seem to find an applied example that shows the relevant MPlus syntax (including setting free vs. equal factor loadings, free vs. fixed error variances, etc) and guide to understanding the related output. Would you be so kind as to direct me to a simple applied example or provide the syntax in a reply? I’m relatively new to MPlus and I have a weak background in stats. Many thanks, Sean 


See the Topic 4 course handout starting with slide 77. 

Sean Tucker posted on Thursday, August 27, 2009  11:14 am



Many thanks, Linda. I received an error message (i.e., "*** ERROR in MODEL command Unknown variable(s) in a BY statement: (1) ") when running the model with factor loading invariance: V1 BY v11 v12 v13 v14 v15 v16 v17 (1)(6); V2 BY v21 v22 v23 v24 v25 v26 v27 (1)(6); V3 BY v31 v32 v33 v34 v35 v36 v37 (1)(6); Pages 532533 of the user manual describe the syntax for fixing parameter values. Would you be so kind has to describe what (1) – (6) means in expanded form. Should I be using different command for fixing the parameter values? Thank you for your help. Sean 


It should say (16). 

Sean Tucker posted on Thursday, August 27, 2009  1:21 pm



Thank you, Linda. Should I be concerned about this message? *** WARNING in MODEL command There are more equality labels given than there are parameters. Some equality labels will not be used. Equality: 16 When testing for partial intercept invariance some items do not appear in the commands on slide 90 (Topic 4). How do I determine which items are not subject to the equality constraint? Thank you, Sean 


Please send your output and license number to support@statmodel.com regarding the error message. Partial measurement invariance requires relaxing the equality constraints of some items which. Modification indices were used to determine which items. The Topic 1 course video covers testing for measurement invariance. You should listen to that and then the Topic 4 course video for a full explanation. 

Pamela May posted on Thursday, August 14, 2014  3:14 pm



Hello, I am testing measurement invariance for a latent difference model. I have the same construct, activity frequency, being tested at two time points. I am confused by the fact that I have the same degrees of freedom, for when I fix the factor loadings (chisquare = 27.30, df = 18), as well as when the factor loadings and the intercepts are fixed (chisquare = 350.02, df = 18). Would there be any reason that these two models have the same degrees of freedom? !Fixing factor loadings CA08 BY dv kv (1) lv (2) pv (3); CA12 BY Ev Mv (1) Nv (2) Rv (3); dv with Ev; kv with Mv; lv with Nv; pv with Rv; CA08 with CA12; !Fixing factor loadings and intercepts (same syntax as before plus this below) !Indicators are categorical, with five levels [dv$4 Ev$4] (4); [kv$4 Mv$4] (5); [lv$4 Nv$4] (6); [pv$4 Rv$4] (7); {dv@1 kv@1 lv@1 pv@1 Ev Mv Nv Rv}; Thank you, Pam 


If you have fixed scale factors at time 2 for the equal loading run, the equal loading+threshold run restricts 4 thresholds but frees 4 scale factors, so ends up with the same number of parameters. Now, in the second model you want to have the factor mean free at time 2. 

Pamela May posted on Thursday, August 14, 2014  3:42 pm



Thank you, Bengt, for your prompt and helpful reply! 

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