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Error message: Latent Factors correla... |
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Message/Author |
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Hello, My goal is to fit a LCSM over 3 measurement time points . To establish basic model structure, I first fit a latent state model with three time points and autocorrelated neighboring error variables: MODEL: reas1 by LPS3_T1 LPS4_T1; reas2 by LPS3_T2 LPS4_T2; reas3 by LPS3_T3 LPS4_T3; ! specification of autocorrelated error variables LPS4_T1 with LPS4_T2; LPS4_T2 with LPS4_T3; LPS3_T1 with LPS3_T2; LPS3_T2 with LPS3_T3; I received the following error message: WARNING: THE LATENT VARIABLE COVARIANCE MATRIX (PSI) IS NOT POSITIVE DEFINITE. THIS COULD INDICATE A NEGATIVE/RESIDUAL VARIANCE FOR A LATENT VARIABLE, A CORRELATION GREATER OR EQUAL TO ONE BETWEEN TWO LATENT VARIABLES, OR A LINEAR DEPENDENCY AMONG MORE THAN TWO LATENT VARIABLES. CHECK THE TECH4 OUTPUT FOR MORE INFORMATION. PROBLEM INVOLVING VARIABLE REAS2. The same happened for other factors with two indicators that I wanted to fit - but not for a factor with three indicators (this fit very well). The same problem occurred for all models: the latent variables were correlated > than 1. When I started to fix these correlations to 1, the problem just shifted to other variables and yielded negative variances... I wonder if the problem lies in my model specification for the two-indicator solution, or is it possible that this simple model does not fit my data? Thanks for your help! Jessica |
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This message usually means that the model needs to be changed. |
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