% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/methods_base.R, R/methods_brms.R,
%   R/methods_rstanarm.R
\name{model_parameters.data.frame}
\alias{model_parameters.data.frame}
\alias{model_parameters.brmsfit}
\alias{model_parameters.stanreg}
\title{Parameters from Bayesian Models}
\usage{
\method{model_parameters}{data.frame}(
  model,
  centrality = "median",
  dispersion = FALSE,
  ci = 0.95,
  ci_method = "hdi",
  test = c("pd", "rope"),
  rope_range = "default",
  rope_ci = 0.95,
  keep = NULL,
  drop = NULL,
  parameters = keep,
  verbose = TRUE,
  ...
)

\method{model_parameters}{brmsfit}(
  model,
  centrality = "median",
  dispersion = FALSE,
  ci = 0.95,
  ci_method = "hdi",
  test = c("pd", "rope"),
  rope_range = "default",
  rope_ci = 0.95,
  bf_prior = NULL,
  diagnostic = c("ESS", "Rhat"),
  priors = FALSE,
  effects = "fixed",
  component = "all",
  exponentiate = FALSE,
  standardize = NULL,
  group_level = FALSE,
  keep = NULL,
  drop = NULL,
  parameters = keep,
  verbose = TRUE,
  ...
)

\method{model_parameters}{stanreg}(
  model,
  centrality = "median",
  dispersion = FALSE,
  ci = 0.95,
  ci_method = "hdi",
  test = c("pd", "rope"),
  rope_range = "default",
  rope_ci = 0.95,
  bf_prior = NULL,
  diagnostic = c("ESS", "Rhat"),
  priors = TRUE,
  effects = "fixed",
  exponentiate = FALSE,
  standardize = NULL,
  group_level = FALSE,
  keep = NULL,
  drop = NULL,
  parameters = keep,
  verbose = TRUE,
  ...
)
}
\arguments{
\item{model}{Bayesian model (including SEM from \pkg{blavaan}. May also be
a data frame with posterior samples.}

\item{centrality}{The point-estimates (centrality indices) to compute.  Character (vector) or list with one or more of these options: \code{"median"}, \code{"mean"}, \code{"MAP"} or \code{"all"}.}

\item{dispersion}{Logical, if \code{TRUE}, computes indices of dispersion related to the estimate(s) (\code{SD} and \code{MAD} for \code{mean} and \code{median}, respectively).}

\item{ci}{Credible Interval (CI) level. Default to \code{0.95} (\verb{95\%}). See
\code{\link[bayestestR:ci]{bayestestR::ci()}} for further details.}

\item{ci_method}{Method for computing degrees of freedom for
confidence intervals (CI) and the related p-values. Allowed are following
options (which vary depending on the model class): \code{"residual"},
\code{"normal"}, \code{"likelihood"}, \code{"satterthwaite"}, \code{"kenward"}, \code{"wald"},
\code{"profile"}, \code{"boot"}, \code{"uniroot"}, \code{"ml1"}, \code{"betwithin"}, \code{"hdi"},
\code{"quantile"}, \code{"ci"}, \code{"eti"}, \code{"si"}, \code{"bci"}, or \code{"bcai"}. See section
\emph{Confidence intervals and approximation of degrees of freedom} in
\code{\link[=model_parameters]{model_parameters()}} for further details. When \code{ci_method=NULL}, in most
cases \code{"wald"} is used then.}

\item{test}{The indices of effect existence to compute. Character (vector) or
list with one or more of these options: \code{"p_direction"} (or \code{"pd"}),
\code{"rope"}, \code{"p_map"}, \code{"equivalence_test"} (or \code{"equitest"}),
\code{"bayesfactor"} (or \code{"bf"}) or \code{"all"} to compute all tests.
For each "test", the corresponding \pkg{bayestestR} function is called
(e.g. \code{\link[bayestestR:rope]{rope()}} or \code{\link[bayestestR:p_direction]{p_direction()}}) and its results
included in the summary output.}

\item{rope_range}{ROPE's lower and higher bounds. Should be a list of two
values (e.g., \code{c(-0.1, 0.1)}) or \code{"default"}. If \code{"default"},
the bounds are set to \code{x +- 0.1*SD(response)}.}

\item{rope_ci}{The Credible Interval (CI) probability, corresponding to the
proportion of HDI, to use for the percentage in ROPE.}

\item{keep}{Character containing a regular expression pattern that
describes the parameters that should be included (for \code{keep}) or excluded
(for \code{drop}) in the returned data frame. \code{keep} may also be a
named list of regular expressions. All non-matching parameters will be
removed from the output. If \code{keep} is a character vector, every parameter
name in the \emph{"Parameter"} column that matches the regular expression in
\code{keep} will be selected from the returned data frame (and vice versa,
all parameter names matching \code{drop} will be excluded). Furthermore, if
\code{keep} has more than one element, these will be merged with an \code{OR}
operator into a regular expression pattern like this: \code{"(one|two|three)"}.
If \code{keep} is a named list of regular expression patterns, the names of the
list-element should equal the column name where selection should be
applied. This is useful for model objects where \code{model_parameters()}
returns multiple columns with parameter components, like in
\code{\link[=model_parameters.lavaan]{model_parameters.lavaan()}}. Note that the regular expression pattern
should match the parameter names as they are stored in the returned data
frame, which can be different from how they are printed. Inspect the
\verb{$Parameter} column of the parameters table to get the exact parameter
names.}

\item{drop}{Character containing a regular expression pattern that
describes the parameters that should be included (for \code{keep}) or excluded
(for \code{drop}) in the returned data frame. \code{keep} may also be a
named list of regular expressions. All non-matching parameters will be
removed from the output. If \code{keep} is a character vector, every parameter
name in the \emph{"Parameter"} column that matches the regular expression in
\code{keep} will be selected from the returned data frame (and vice versa,
all parameter names matching \code{drop} will be excluded). Furthermore, if
\code{keep} has more than one element, these will be merged with an \code{OR}
operator into a regular expression pattern like this: \code{"(one|two|three)"}.
If \code{keep} is a named list of regular expression patterns, the names of the
list-element should equal the column name where selection should be
applied. This is useful for model objects where \code{model_parameters()}
returns multiple columns with parameter components, like in
\code{\link[=model_parameters.lavaan]{model_parameters.lavaan()}}. Note that the regular expression pattern
should match the parameter names as they are stored in the returned data
frame, which can be different from how they are printed. Inspect the
\verb{$Parameter} column of the parameters table to get the exact parameter
names.}

\item{parameters}{Deprecated, alias for \code{keep}.}

\item{verbose}{Toggle messages and warnings.}

\item{...}{Currently not used.}

\item{bf_prior}{Distribution representing a prior for the computation of
Bayes factors / SI. Used if the input is a posterior, otherwise (in the
case of models) ignored.}

\item{diagnostic}{Diagnostic metrics to compute.  Character (vector) or list
with one or more of these options: \code{"ESS"}, \code{"Rhat"}, \code{"MCSE"} or \code{"all"}.}

\item{priors}{Add the prior used for each parameter.}

\item{effects}{Should results for fixed effects, random effects or both be
returned? Only applies to mixed models. May be abbreviated.}

\item{component}{Which type of parameters to return, such as parameters for the
conditional model, the zero-inflated part of the model, the dispersion
term, or other auxiliary parameters be returned? Applies to models with
zero-inflated and/or dispersion formula, or if parameters such as \code{sigma}
should be included. May be abbreviated. Note that the \emph{conditional}
component is also called \emph{count} or \emph{mean} component, depending on the
model. There are three convenient shortcuts: \code{component = "all"} returns
all possible parameters. If \code{component = "location"}, location parameters
such as \code{conditional}, \code{zero_inflated}, or \code{smooth_terms}, are returned
(everything that are fixed or random effects - depending on the \code{effects}
argument - but no auxiliary parameters). For \code{component = "distributional"}
(or \code{"auxiliary"}), components like \code{sigma}, \code{dispersion}, or \code{beta}
(and other auxiliary parameters) are returned.}

\item{exponentiate}{Logical, indicating whether or not to exponentiate the
the coefficients (and related confidence intervals). This is typical for
logistic regression, or more generally speaking, for models with log
or logit links. \strong{Note:} Delta-method standard errors are also
computed (by multiplying the standard errors by the transformed
coefficients). This is to mimic behaviour of other software packages, such
as Stata, but these standard errors poorly estimate uncertainty for the
transformed coefficient. The transformed confidence interval more clearly
captures this uncertainty. For \code{compare_parameters()},
\code{exponentiate = "nongaussian"} will only exponentiate coefficients
from non-Gaussian families.}

\item{standardize}{The method used for standardizing the parameters. Can be
\code{NULL} (default; no standardization), \code{"refit"} (for re-fitting the model
on standardized data) or one of \code{"basic"}, \code{"posthoc"}, \code{"smart"},
\code{"pseudo"}. See 'Details' in \code{\link[effectsize:standardize_parameters]{effectsize::standardize_parameters()}}.
\strong{Important:}
\itemize{
\item The \code{"refit"} method does \emph{not} standardized categorical predictors (i.e.
factors), which may be a different behaviour compared to other R packages
(such as \pkg{lm.beta}) or other software packages (like SPSS). to mimic
such behaviours, either use \code{standardize="basic"} or standardize the data
with \code{datawizard::standardize(force=TRUE)} \emph{before} fitting the model.
\item For mixed models, when using methods other than \code{"refit"}, only the fixed
effects will be returned.
\item Robust estimation (i.e. \code{robust=TRUE}) of standardized parameters only
works when \code{standardize="refit"}.
}}

\item{group_level}{Logical, for multilevel models (i.e. models with random
effects) and when \code{effects = "all"} or \code{effects = "random"},
include the parameters for each group level from random effects. If
\code{group_level = FALSE} (the default), only information on SD and COR
are shown.}
}
\value{
A data frame of indices related to the model's parameters.
}
\description{
Parameters from Bayesian models.
}
\note{
When \code{standardize = "refit"}, columns \code{diagnostic},
\code{bf_prior} and \code{priors} refer to the \emph{original}
\code{model}. If \code{model} is a data frame, arguments \code{diagnostic},
\code{bf_prior} and \code{priors} are ignored. \cr \cr There is also a
\href{https://easystats.github.io/see/articles/parameters.html}{\code{plot()}-method}
implemented in the
\href{https://easystats.github.io/see/}{\pkg{see}-package}.
}
\section{Confidence intervals and approximation of degrees of freedom}{

There are different ways of approximating the degrees of freedom depending
on different assumptions about the nature of the model and its sampling
distribution. The \code{ci_method} argument modulates the method for computing degrees
of freedom (df) that are used to calculate confidence intervals (CI) and the
related p-values. Following options are allowed, depending on the model
class:

\strong{Classical methods:}

Classical inference is generally based on the \strong{Wald method}.
The Wald approach to inference computes a test statistic by dividing the
parameter estimate by its standard error (Coefficient / SE),
then comparing this statistic against a t- or normal distribution.
This approach can be used to compute CIs and p-values.

\code{"wald"}:
\itemize{
\item Applies to \emph{non-Bayesian models}. For \emph{linear models}, CIs
computed using the Wald method (SE and a \emph{t-distribution with residual df});
p-values computed using the Wald method with a \emph{t-distribution with residual df}.
For other models, CIs computed using the Wald method (SE and a \emph{normal distribution});
p-values computed using the Wald method with a \emph{normal distribution}.
}

\code{"normal"}
\itemize{
\item Applies to \emph{non-Bayesian models}. Compute Wald CIs and p-values,
but always use a normal distribution.
}

\code{"residual"}
\itemize{
\item Applies to \emph{non-Bayesian models}. Compute Wald CIs and p-values,
but always use a \emph{t-distribution with residual df} when possible. If the
residual df for a model cannot be determined, a normal distribution is
used instead.
}

\strong{Methods for mixed models:}

Compared to fixed effects (or single-level) models, determining appropriate
df for Wald-based inference in mixed models is more difficult.
See \href{https://bbolker.github.io/mixedmodels-misc/glmmFAQ.html#what-are-the-p-values-listed-by-summaryglmerfit-etc.-are-they-reliable}{the R GLMM FAQ}
for a discussion.

Several approximate methods for computing df are available, but you should
also consider instead using profile likelihood (\code{"profile"}) or bootstrap ("\verb{boot"})
CIs and p-values instead.

\code{"satterthwaite"}
\itemize{
\item Applies to \emph{linear mixed models}. CIs computed using the
Wald method (SE and a \emph{t-distribution with Satterthwaite df}); p-values
computed using the Wald method with a \emph{t-distribution with Satterthwaite df}.
}

\code{"kenward"}
\itemize{
\item Applies to \emph{linear mixed models}. CIs computed using the Wald
method (\emph{Kenward-Roger SE} and a \emph{t-distribution with Kenward-Roger df});
p-values computed using the Wald method with \emph{Kenward-Roger SE and t-distribution with Kenward-Roger df}.
}

\code{"ml1"}
\itemize{
\item Applies to \emph{linear mixed models}. CIs computed using the Wald
method (SE and a \emph{t-distribution with m-l-1 approximated df}); p-values
computed using the Wald method with a \emph{t-distribution with m-l-1 approximated df}.
See \code{\link[=ci_ml1]{ci_ml1()}}.
}

\code{"betwithin"}
\itemize{
\item Applies to \emph{linear mixed models} and \emph{generalized linear mixed models}.
CIs computed using the Wald method (SE and a \emph{t-distribution with between-within df});
p-values computed using the Wald method with a \emph{t-distribution with between-within df}.
See \code{\link[=ci_betwithin]{ci_betwithin()}}.
}

\strong{Likelihood-based methods:}

Likelihood-based inference is based on comparing the likelihood for the
maximum-likelihood estimate to the the likelihood for models with one or more
parameter values changed (e.g., set to zero or a range of alternative values).
Likelihood ratios for the maximum-likelihood and alternative models are compared
to a \eqn{\chi}-squared distribution to compute CIs and p-values.

\code{"profile"}
\itemize{
\item Applies to \emph{non-Bayesian models} of class \code{glm}, \code{polr} or \code{glmmTMB}.
CIs computed by \emph{profiling the likelihood curve for a parameter}, using
linear interpolation to find where likelihood ratio equals a critical value;
p-values computed using the Wald method with a \emph{normal-distribution} (note:
this might change in a future update!)
}

\code{"uniroot"}
\itemize{
\item Applies to \emph{non-Bayesian models} of class \code{glmmTMB}. CIs
computed by \emph{profiling the likelihood curve for a parameter}, using root
finding to find where likelihood ratio equals a critical value; p-values
computed using the Wald method with a \emph{normal-distribution} (note: this
might change in a future update!)
}

\strong{Methods for bootstrapped or Bayesian models:}

Bootstrap-based inference is based on \strong{resampling} and refitting the model
to the resampled datasets. The distribution of parameter estimates across
resampled datasets is used to approximate the parameter's sampling
distribution. Depending on the type of model, several different methods for
bootstrapping and constructing CIs and p-values from the bootstrap
distribution are available.

For Bayesian models, inference is based on drawing samples from the model
posterior distribution.

\code{"quantile"} (or \code{"eti"})
\itemize{
\item Applies to \emph{all models (including Bayesian models)}.
For non-Bayesian models, only applies if \code{bootstrap = TRUE}. CIs computed
as \emph{equal tailed intervals} using the quantiles of the bootstrap or
posterior samples; p-values are based on the \emph{probability of direction}.
See \code{\link[bayestestR:eti]{bayestestR::eti()}}.
}

\code{"hdi"}
\itemize{
\item Applies to \emph{all models (including Bayesian models)}. For non-Bayesian
models, only applies if \code{bootstrap = TRUE}. CIs computed as \emph{highest density intervals}
for the bootstrap or posterior samples; p-values are based on the \emph{probability of direction}.
See \code{\link[bayestestR:hdi]{bayestestR::hdi()}}.
}

\code{"bci"} (or \code{"bcai"})
\itemize{
\item Applies to \emph{all models (including Bayesian models)}.
For non-Bayesian models, only applies if \code{bootstrap = TRUE}. CIs computed
as \emph{bias corrected and accelerated intervals} for the bootstrap or
posterior samples; p-values are based on the \emph{probability of direction}.
See \code{\link[bayestestR:bci]{bayestestR::bci()}}.
}

\code{"si"}
\itemize{
\item Applies to \emph{Bayesian models} with proper priors. CIs computed as
\emph{support intervals} comparing the posterior samples against the prior samples;
p-values are based on the \emph{probability of direction}. See \code{\link[bayestestR:si]{bayestestR::si()}}.
}

\code{"boot"}
\itemize{
\item Applies to \emph{non-Bayesian models} of class \code{merMod}. CIs computed
using \emph{parametric bootstrapping} (simulating data from the fitted model);
p-values computed using the Wald method with a \emph{normal-distribution)}
(note: this might change in a future update!).
}

For all iteration-based methods other than \code{"boot"}
(\code{"hdi"}, \code{"quantile"}, \code{"ci"}, \code{"eti"}, \code{"si"}, \code{"bci"}, \code{"bcai"}),
p-values are based on the probability of direction (\code{\link[bayestestR:p_direction]{bayestestR::p_direction()}}),
which is converted into a p-value using \code{\link[bayestestR:pd_to_p]{bayestestR::pd_to_p()}}.
}

\examples{
\dontrun{
library(parameters)
if (require("rstanarm")) {
  model <- stan_glm(
    Sepal.Length ~ Petal.Length * Species,
    data = iris, iter = 500, refresh = 0
  )
  model_parameters(model)
}
}
}
\seealso{
\code{\link[insight:standardize_names]{insight::standardize_names()}} to
rename columns into a consistent, standardized naming scheme.
}
