An embedded and charset-unspecified text was scrubbed... Name: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130221/6c0fce6f/attachment.pl>
total indirect effects in structural equation modeling using lavaan
5 messages · Marios, yrosseel
On 02/21/2013 03:59 PM, Marios wrote:
My question.......I would like to calculate the total indirect effects of all variables on the right-hand-side of the regression eqn's so that i can work out the total effect (indirect effects + direct effect) I know the direct effect and i can calculate the total indirect effects by hand but i was wondering if there is a function that can calculate this?
In the current version of lavaan (0.5-11), there is no function that will compute all possible indirect/total effects automatically. What you can do is to label the coefficients, and then use the ':=' operator to define the total/indirect effects that you are interested in. Next, you could use se="boot" to get a bootstrap based SE. See the lavaan paper (http://www.jstatsoft.org/v48/i02/) section 7.4 for an example. Yves.
An embedded and charset-unspecified text was scrubbed... Name: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130222/383d7462/attachment.pl>
On 02/22/2013 11:40 AM, Marios wrote:
Thank you very much Yves! I have managed to get the total indirect effects that i wanted but it seems to only work on the unstandardized coefficients. I use "standardized =TRUE" in the "summary" command but the "std.all" column has the same values as the "Estimate" (unstandardized) column for the new parameters defined by the ":=" operator. All other parameters i.e. using "~" have been standardized. How do i go about calculating the indirect effects based on standardized coefficients?
You need to install 0.5-12, where the newly 'defined' parameters
(defined by the ":=" operator) are standardized too (just like the other
parameters). This version is not on CRAN yet, but you can install it by
typing in R:
install.packages("lavaan", repos="http://www.da.ugent.be", type="source")
Yves.
Yves Rosseel -- http://www.da.ugent.be Department of Data Analysis, Ghent University http://lavaan.org
An embedded and charset-unspecified text was scrubbed... Name: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130222/2a951e37/attachment.pl>