plot.loglike_compare: Plot the Output of 'loglike_compare()'

In semlbci: Likelihood-Based Confidence Interval in Structural Equation Models

Plot the Output of 'loglike_compare()'

Description

Visualize the log profile likelihood of a parameter fixed to values in a range.

Usage

## S3 method for class 'loglike_compare'
plot(
  x,
  y,
  type = c("ggplot2", "default"),
  size_label = 4,
  size_point = 4,
  nd_theta = 3,
  nd_pvalue = 3,
  size_theta = 4,
  size_pvalue = 4,
  add_pvalues = FALSE,
  ...
)

Arguments

x	The output of loglike_compare().
y	Not used.
type	Character. If "ggplot2", will use ggplot2::ggplot() to plot the graph. If "default", will use R base graphics, The ggplot2 version plots more information. Default is "ggplot2".
size_label	The relative size of the labels for thetas (and p-values, if requested) in the plot, determined by ggplot2::rel(). Default is 4.
size_point	The relative size of the points to be added if p-values are requested in the plot, determined by ggplot2::rel(). Default is 4.
nd_theta	The number of decimal places for the labels of theta. Default is 3.
nd_pvalue	The number of decimal places for the labels of p-values. Default is 3.
size_theta	Deprecated. No longer used.
size_pvalue	Deprecated. No longer used.
add_pvalues	If TRUE, likelihood ratio test p-values will be included for the confidence limits. Only available if type = "ggplot2".
...	Optional arguments. Ignored.

Details

Given the output of loglike_compare(), it plots the log profile likelihood based on quadratic approximation and that based on the original log-likelihood. The log profile likelihood is scaled to have a maximum of zero (at the point estimate) as suggested by Pawitan (2013).

Value

Nothing if type = "default", the generated ggplot2::ggplot() graph if type = "ggplot2".

References

Pawitan, Y. (2013). In all likelihood: Statistical modelling and inference using likelihood. Oxford University Press.

Examples

## loglike_compare

library(lavaan)
data(simple_med)
dat <- simple_med
mod <-
"
m ~ a * x
y ~ b * m
ab := a * b
"
fit <- lavaan::sem(mod, simple_med, fixed.x = FALSE)

# Four points are used just for illustration
# At least 21 points should be used for a smooth plot
# Remove try_k_more in real applications. It is set
# to run such that this example is not too slow.
# use_pbapply can be removed or set to TRUE to show the progress.
ll_a <- loglike_compare(fit, par_i = "m ~ x", n_points = 4,
                        try_k_more = 0,
                        use_pbapply = FALSE)

plot(ll_a)
plot(ll_a, add_pvalues = TRUE)

# See the vignette "loglike" for an example for the
# indirect effect.

semlbci documentation built on June 22, 2024, 10:55 a.m.