R: Draw Path Diagram

pathDiagram {sem}

R Documentation

Draw Path Diagram

Description

pathDiagram creates a description of the path diagram for a structural-equation-model or SEM-specification object to be processed by the graph-drawing program dot, which can be called automatically; see Koutsofios and North (2002) and http://www.graphviz.org/. To obtain graphics output directly, the dot program must be on the system search path. The semmod method sets up a call to the sem method.

Usage

## S3 method for class 'sem'
pathDiagram(model, file, min.rank=NULL, max.rank=NULL,
	same.rank=NULL, variables=model$var.names, parameters,
	ignore.double=TRUE, edge.labels=c("names", "values", "both"), 
	size=c(8, 8), node.font=c("Helvetica", 14),
	edge.font=c("Helvetica", 10), rank.direction=c("LR", "TB"), 
	digits=2, standardize=FALSE, output.type=c("graphics", "dot"),
	graphics.fmt="pdf", dot.options=NULL, ...)

## S3 method for class 'semmod'
pathDiagram(model, obs.variables, ...)

Arguments

`model`	a structural-equation-model or SEM-specification object produced by `sem`, or, respectively, `specifyEquations`, `specifyModel`, or `cfa`.
`...`	arguments passed down, e.g., from the `semmod` method to the `sem` method.
`file`	a file name, given without an extension, to which to write the dot description of the path diagram and, by default, to use that to draw a graph of the model; if not specified, the dot description is written to standard output (normally the R Console). Note that by default (see the `output.type` argument below), two files are written: a ".dot" file and a graphics file of type specified by the `graphics.fmt` argument (below); `file` may include a path specification.
`min.rank`	a character string listing names of variables to be assigned minimum rank (order) in the graph; the names should be separated by commas.
`max.rank`	a character string listing names of variables to be assigned maximum rank in the graph; the names should be separated by commas.
`same.rank`	a character string or vector of character strings of variables to be assigned equivalent rank in the graph; names in each string should be separated by commas.
`variables`	variable names; defaults to the variable names in `model`. If specified, the variable names should be in the same order as in `model`.
`parameters`	parameter names; defaults to the parameter names in `model`. If specified, the parameter names should be in the same order as in `model`.
`ignore.double`	if `TRUE`, the default, double-headed arrows, representing variances and covariances, are not graphed.
`edge.labels`	`"names"` to label arrows with parameter names; `"values"` to label arrows with parameter estimates, or `"both"`.
`size`	the size of the graph, in inches.
`node.font`	font name and point-size for printing variable names.
`edge.font`	font name and point-size for printing arrow names or values.
`rank.direction`	draw graph left-to-right, `"LR"`, the default, or top-to-bottom, `"TB"`.
`digits`	number of digits after the decimal point (default, 2) to which to round parameter estimates.
`standardize`	if `TRUE`, display standardized coefficients; default is `FALSE`.
`output.type`	if `"graphics"`, the default, both a ".dot" file and a graphics file will be created.
`graphics.fmt`	a graphics format recognized by the dot program; the default is `"pdf"`; `graphics.fmt` is also used for the extension of the graphics file that is created.
`dot.options`	options to be passed to the dot program, given as a character string.
`obs.variables`	a character vector with the names of the observed variables in the model.

Value

NULL: pathDiagram is used for its side-effect, producing a graph description of the model.

Author(s)

John Fox jfox@mcmaster.ca, Adam Kramer, and Michael Friendly

References

Koutsofios, E., and North, S. C. (2002) Drawing graphs with dot. http://www.graphviz.org/Documentation/dotguide.pdf.

Examples

	## Not run: 
# The Duncan, Haller, and Portes Peer-Influences Model

R.DHP <- readMoments(diag=FALSE, names=c('ROccAsp', 'REdAsp', 'FOccAsp', 
                'FEdAsp', 'RParAsp', 'RIQ', 'RSES', 'FSES', 'FIQ', 'FParAsp'))
    .6247                                                              
    .3269  .3669                                                        
    .4216  .3275  .6404                                      
    .2137  .2742  .1124  .0839                                
    .4105  .4043  .2903  .2598  .1839                          
    .3240  .4047  .3054  .2786  .0489  .2220                    
    .2930  .2407  .4105  .3607  .0186  .1861  .2707              
    .2995  .2863  .5191  .5007  .0782  .3355  .2302  .2950        
    .0760  .0702  .2784  .1988  .1147  .1021  .0931 -.0438  .2087  

model.dhp <- specifyModel()
    RParAsp  -> RGenAsp, gam11,  NA
    RIQ      -> RGenAsp, gam12,  NA
    RSES     -> RGenAsp, gam13,  NA
    FSES     -> RGenAsp, gam14,  NA
    RSES     -> FGenAsp, gam23,  NA
    FSES     -> FGenAsp, gam24,  NA
    FIQ      -> FGenAsp, gam25,  NA
    FParAsp  -> FGenAsp, gam26,  NA
    FGenAsp  -> RGenAsp, beta12, NA
    RGenAsp  -> FGenAsp, beta21, NA
    RGenAsp  -> ROccAsp,  NA,       1
    RGenAsp  -> REdAsp,  lam21,  NA
    FGenAsp  -> FOccAsp,  NA,       1
    FGenAsp  -> FEdAsp,  lam42,  NA
    RGenAsp <-> RGenAsp, ps11,   NA
    FGenAsp <-> FGenAsp, ps22,   NA
    RGenAsp <-> FGenAsp, ps12,   NA
    ROccAsp <-> ROccAsp, theta1, NA
    REdAsp  <-> REdAsp,  theta2, NA
    FOccAsp <-> FOccAsp, theta3, NA
    FEdAsp  <-> FEdAsp,  theta4, NA

sem.dhp <- sem(model.dhp, R.DHP, 329,
    fixed.x=c('RParAsp', 'RIQ', 'RSES', 'FSES', 'FIQ', 'FParAsp'))
    
pathDiagram(sem.dhp, min.rank='RIQ, RSES, RParAsp, FParAsp, FSES, FIQ', 
    max.rank='ROccAsp, REdAsp, FEdAsp, FOccAsp')
    
      # equivalent:    
pathDiagram(model.dhp, 
    obs.variables=c("RParAsp", "RIQ", "RSES", "FSES", "FIQ", 
      "FParAsp", "ROccAsp", "REdAsp", "FOccAsp", "FEdAsp"),
    min.rank='RIQ, RSES, RParAsp, FParAsp, FSES, FIQ', 
    max.rank='ROccAsp, REdAsp, FEdAsp, FOccAsp',
    same.rank='RGenAsp, FGenAsp') # note crowding of labels
    
## End(Not run)

[Package sem version 3.1-3 Index]