Standard errors of zero using R3STEP PreviousNext
Mplus Discussion > Latent Variable Mixture Modeling >
Message/Author
 Michelle Colder Carras posted on Thursday, August 14, 2014 - 5:53 am
Hi,
Im doing LCA with R3STEP using SUBPOPULATION with some missing data and finding that many standard errors are 0 in the latent class regression. The regression drops a total of 58 observations and uses 651. This problem occurs when using 8 covariates (2 binary, 2 categorical, 4 standardized continuous) and 6 categorical latent class indicators.

All of the categorical covariates have standard errors of 0 in each of the 3 multinomial regressions no matter which class is used as the reference class. For the continuous covariates, this happens only sometimes. For example, when using class 4 as the reference class I get:
C#1 ON

DEPMST1 0.287 0.000 999.000 0.000
LONMST1 0.339 0.181 1.872 0.061

C#2 ON

DEPMST1 -0.460 0.137 -3.361 0.001
LONMST1 0.416 0.000 999.000 0.000

When I attempt to add an additional 3 continuous covariates, an additional 6 observations are dropped and even more SEs become 0. E.g., when using class 4 as the reference class, the SEs for the coefficients for the regressions of both DEPMST1 and LONMST1 are now 0 in the C#1 regression, but the SE is still calculated for DEPMST1 in the regression of C#2.

Thank you for any insight/help you might have.

-Michelle Carras
 Linda K. Muthen posted on Thursday, August 14, 2014 - 9:04 am
It looks like that parameters are being fixed not that the standard errors are zero. For further information, send the output and your license number to support@statmodel.com.
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