an update on the possible mediations with lavaan

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Emmanuel W

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Jul 22, 2019, 8:32:34 AM7/22/19
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Hi all,

I am trying to calculate indirect and total effects but I have read that:

The equation of c = c' + ab exactly holds when a) multiple regression (or structural equation modeling without latent variables) is used, b) the same cases are used in all the analyses, c) and the same covariates are in all the equations.  However, the two are only approximately equal for multilevel models, logistic analysis and structural equation modeling with latent variables.  For such models, it is probably inadvisable to compute c from Step 1, but rather c or the total effect should be inferred to be c' + ab and not directly computed. (website of David Kenny).

It seems to me that lavaan makes it possible to calculate these effects when the mediator and the outcome are binary, but what about when only one of them is binary? Moreover, does lavaan allow these effects to be correctly calculated when the mediator is a latent variable?

Thank you,

Emmanuel

Terrence Jorgensen

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Aug 6, 2019, 11:18:52 AM8/6/19
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what about when only one of them is binary? Moreover, does lavaan allow these effects to be correctly calculated when the mediator is a latent variable? 

Those questions are already answered in the text you provided.  Although lavaan uses a probit rather than logistic regression, the relationship holds only approximately.

Terrence D. Jorgensen
Assistant Professor, Methods and Statistics
Research Institute for Child Development and Education, the University of Amsterdam

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