dSep {piecewiseSEM} | R Documentation |
Evaluation of conditional independence claims to be used in determining the goodness-of-fit for piecewise structural equation models.
dSep(modelList, direction = NULL, conserve = FALSE, conditioning = FALSE, .progressBar = TRUE)
modelList |
A list of structural equations created using |
direction |
A |
conserve |
Whether the most conservative P-value should be returned; for use in special cases (see Details). Default is FALSE. |
conditioning |
Whether the conditioning variables should be shown in the summary table. Default is FALSE. |
.progressBar |
An optional progress bar. Default is TRUE. |
In cases involving non-normally distributed responses in the independence
claims that are modeled using generalized linear models, the significance of
the independence claim is not reversable (e.g., the P-value of Y ~ X is not
the same as X ~ Y). This is due to the transformation of the response via
the link function. In extreme cases, this can bias the goodness-of-fit
tests. summary.psem
will issue a warning when this case is present
and provide guidance for solutions.
One solution is to specify the directionality of the relationship using the
direction
argument, e.g. direction = c("X <- Y")
. Another is
to run both tests (Y ~ X, X ~ Y) and return the most conservative (i.e.,
lowest) P-value, which can be toggled using the conserve = TRUE
argument.
Returns a data.frame
of independence claims and their
significance values.
Jon Lefcheck <jlefcheck@bigelow.org>
Shipley, Bill. "A new inferential test for path models based on directed acyclic graphs." Structural Equation Modeling 7.2 (2000): 206-218.