fa.diagram {psych}R Documentation

Graph factor loading matrices

Description

Factor analysis or principal components analysis results are typically interpreted in terms of the major loadings on each factor. These structures may be represented as a table of loadings or graphically, where all loadings with an absolute value > some cut point are represented as an edge (path).

Usage

fa.diagram(fa.results,sort=TRUE,labels=NULL,cut=.3,simple=TRUE,errors=FALSE,
    digits=1,e.size=.05,rsize=.15,side=2,main="Factor Analysis",cex=NULL, ...) 
fa.graph(fa.results,out.file=NULL,labels=NULL,cut=.3,simple=TRUE,
   size=c(8,6), node.font=c("Helvetica", 14),
    edge.font=c("Helvetica", 10), rank.direction=c("RL","TB","LR","BT"), digits=1,main="Factor Analysis",graphviz=TRUE, ...)

Arguments

fa.results The output of factor analysis or principal components analysis
out.file If it exists, a dot representation of the graph will be stored here (fa.graph)
labels Variable labels
cut Loadings with abs(loading) > cut will be shown
simple Only the biggest loading per item is shown
size graph size
sort sort the factor loadings before showing the diagram
errors include error estimates (as arrows)
e.size size of ellipses
rsize size of rectangles
side on which side should error arrows go?
cex modify font size
node.font
edge.font
rank.direction
digits Number of digits to show as an edgelable
main Graphic title
graphviz Should we try to use Rgraphviz for output?
... other parameters

Details

Path diagram representations have become standard in confirmatory factor analysis, but are not yet common in exploratory factor analysis. Representing factor structures graphically helps some people understand the structure.

fa.diagram does not use Rgraphviz and is the preferred function.

In fa.graph, although a nice graph is drawn for the orthogonal factor case, the oblique factor drawing is acceptable, but is better if cleaned up outside of R.

Value

fa.diagram: A path diagram is drawn without using Rgraphviz. This is probably the more useful function.
fa.graph: A graph is drawn using rgraphviz. If an output file is specified, the graph instructions are also saved in the dot language.

Note

fa.graph requires Rgraphviz. Because there are occasional difficulties installing Rgraphviz from Bioconductor in that some libraries are misplaced and need to be relinked, it is probably better to use fa.diagram.

As of June 1, 2007 there is an occasionally strange result when using the simple=FALSE option in Sweave.

Author(s)

William Revelle

See Also

omega.graph, ICLUST.graph

Examples


test.simple <- fa(item.sim(16),2,rotate="oblimin")
#if(require(Rgraphviz)) {fa.graph(test.simple) } 
fa.diagram(test.simple)
data(bifactor)
fa.diagram(fa(Thurstone,3,rotate="cluster"),cut=.4,digits=2)


[Package psych version 1.0-85 Index]