R help - May 2010 - [R-pkgs] New package: `lavaan' for latent variable analysis (including structural equation modeling)

Hi Yves

lavaan looks like a very nice package.  From the tutorial introduction
I see you create path diagrams for some of the models you describe.
How did you do this?  I don't see a function for this in the package.

I know there is a path.diagram function in the sem package that uses
dot to draw the diagram, but I've always found the layouts from dot
somewhat strange for path diagrams without a fair bit of tweaking.

-Michael



Yves Rosseel wrote:
> Dear R-users,
> 
> A new package called `lavaan' (for latent variable analysis) has been 
> uploaded to CRAN. The current version of lavaan (0.3-1) can be used for 
> path analysis, confirmatory factor analysis, structural equation 
> modeling, and growth curve modeling.
> 
> More information can be found on the website: http://lavaan.org
> 
> Some notable features of lavaan:
> 
> - the 'lavaan model syntax' allows users to express their models in
a
> compact, elegant and useR-friendly way
> 
> - lavaan is robust and reliable: there are no convergence problems and 
> numerical results are very close (if not identical) to the commercial 
> package Mplus
> 
> - many different estimators are available: ML, GLS, WLS, robust ML using 
> Satorra-Bentler corrections, and FIML for data with missing values
> 
> - full support for meanstructures and multiple groups
> 
> - user friendly output including standardized solutions, fit measures, 
> modification indices and more
> 
> To get a first impression of how the 'lavaan model syntax' looks
like,
> below is the full R code for fitting a SEM model:
> 
> ## begin R Code ##
> 
> library(lavaan)
> 
> # The industrialization and Political Democracy Example
> # Bollen (1989), page 332
> 
> model <- '
>   # latent variable definitions
>      ind60 =~ x1 + x2 + x3
>      dem60 =~ y1 + y2 + y3 + y4
>      dem65 =~ y5 + y6 + y7 + y8
> 
>   # regressions
>     dem60 ~ ind60
>     dem65 ~ ind60 + dem60
> 
>   # residual correlations
>     y1 ~~ y5
>     y2 ~~ y4 + y6
>     y3 ~~ y7
>     y4 ~~ y8
>     y6 ~~ y8
> '
> 
> fit <- sem(model, data=PoliticalDemocracy)
> summary(fit, fit.measures=TRUE)
> 
> ## end R code ##
> 
> 
> Please feel free to contact me directly with questions and comments.
> 
> Best,
> 
> Yves Rosseel.
> 
> 
>

On 05/24/2010 06:31 PM, Michael Friendly wrote:
> Hi Yves
>
> lavaan looks like a very nice package. From the tutorial introduction
> I see you create path diagrams for some of the models you describe.
> How did you do this? I don't see a function for this in the package.
>
> I know there is a path.diagram function in the sem package that uses
> dot to draw the diagram, but I've always found the layouts from dot
> somewhat strange for path diagrams without a fair bit of tweaking.
There is currently no function in lavaan to automatically draw a path 
diagram. The path diagrams in the tutorial are handmade in latex, using 
the tikz/pgf environment.

Best,

Yves Rosseel.

On 05/24/2010 09:53 PM, JLucke at ria.buffalo.edu wrote:
>
> Yves
> Would it by to much to ask of you to supply a copy of your LaTeX for the
> tikz/pgf? I would like to learn tikz/pgf and your pictures are
> motivating examples.
> Joe
When I find the time, I will put the complete latex source of the 
tutorial on the webpage. But the tikz/pgf code for the second example is 
given below:

%% this goes in the latex preamble
\usepackage{tikz}
\tikzstyle{ov}=[shape=rectangle,
                 draw=black!80,
                 minimum height=0.75cm,
                 minimum width=1cm,
                 thick]

\tikzstyle{av}=[shape=rectangle,
                 draw=black!80,
                 fill=black!10,
                 minimum height=1cm,
                 minimum width=1cm,
                 thick]

\tikzstyle{lv}=[shape=circle,draw=black!80,thick,minimum width=1.5cm]

%% this the tikz code for the SEM example
\begin{center}
\begin{tabular}{p{0.5\textwidth}p{0.4\textwidth}} \hline
\begin{center}
\begin{tikzpicture}[>=stealth,semithick,scale=0.6]
\node[ov] (y1) at (0,0)     {\code{y1}};
\node[ov] (y2) at (0,-1.4)  {\code{y2}};
\node[ov] (y3) at (0,-2.8)  {\code{y3}};
\node[ov] (y4) at (0,-4.2)  {\code{y4}};
\node[ov] (y5) at (0,-5.6)  {\code{y5}};
\node[ov] (y6) at (0,-7)    {\code{y6}};
\node[ov] (y7) at (0,-8.4)  {\code{y7}};
\node[ov] (y8) at (0,-9.8)  {\code{y8}};
\node[ov] (x1) at ( 6,0)     {\code{x1}};
\node[ov] (x2) at ( 8,0)     {\code{x2}};
\node[ov] (x3) at (10,0)     {\code{x3}};
\node[lv] (f1) at (4, -2.8) {\code{dem60}};
\node[lv] (f2) at (4, -7.6) {\code{dem65}};
\node[lv] (f3) at (8, -2.8) {\code{ind60}};
\path[->] (f1) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y1.east);
\path[->] (f1) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y2.east);
\path[->] (f1) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y3.east);
\path[->] (f1) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y4.east);
\path[->] (f2) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y5.east);
\path[->] (f2) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y6.east);
\path[->] (f2) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y7.east);
\path[->] (f2) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (y8.east);
\path[->] (f3) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (x1.south);
\path[->] (f3) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (x2.south);
\path[->] (f3) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (x3.south);
\path[->] (f1) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (f2);
\path[->] (f3) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (f1.east);
\path[->] (f3) edge node[above=0.08cm,scale=0.8,pos=0.7] {} (f2.north east);
\path[<->] (y1.west) edge [bend right=45] node[left,scale=0.8] {}
(y5.west);
\path[<->] (y2.west) edge [bend right=45] node[left,scale=0.8] {}
(y6.west);
\path[<->] (y3.west) edge [bend right=45] node[left,scale=0.8] {}
(y7.west);
\path[<->] (y4.west) edge [bend right=45] node[left,scale=0.8] {}
(y8.west);
\path[<->] (y2.south west) edge [bend right=45] node[left,scale=0.8] {} 
(y4.north west);
\path[<->] (y6.south west) edge [bend right=45] node[left,scale=0.8] {} 
(y8.north west);
\end{tikzpicture}
\end{center}

-- 
Yves Rosseel -- http://www.da.ugent.be
Department of Data Analysis, Ghent University
Henri Dunantlaan 1, B-9000 Gent, Belgium