From 9edba3129e92554e36c25601283053f0a2b9aa14 Mon Sep 17 00:00:00 2001
From: Daniel <mail@danielluedecke.de>
Date: Tue, 23 Jul 2024 23:18:36 +0200
Subject: [PATCH] remove degrees_of_freedom methods

---
 NAMESPACE                 |  56 ----------
 R/compare_parameters.R    |  16 +++
 R/dof.R                   | 212 +-------------------------------------
 R/extract_parameters.R    |   2 +-
 R/methods_BBMM.R          |  15 ---
 R/methods_bfsl.R          |  17 ---
 R/methods_biglm.R         |   9 --
 R/methods_brglm2.R        |  13 ---
 R/methods_cgam.R          |  35 -------
 R/methods_effect_size.R   |  14 +--
 R/methods_emmeans.R       | 107 ++++++-------------
 R/methods_fixest.R        |  44 --------
 R/methods_gee.R           |   2 +-
 R/methods_hglm.R          |   9 --
 R/methods_ivfixed.R       |  21 +---
 R/methods_ivprobit.R      |   5 -
 R/methods_lm.R            |   6 --
 R/methods_lmtest.R        |   5 -
 R/methods_lqmm.R          |  11 --
 R/methods_lrm.R           |   8 +-
 R/methods_mass.R          |  24 +----
 R/methods_mediate.R       |   6 --
 R/methods_merTools.R      |   7 --
 R/methods_mfx.R           |  44 --------
 R/methods_mhurdle.R       |   6 --
 R/methods_mice.R          |  15 ---
 R/methods_mmrm.R          |  15 ---
 R/methods_model_fit.R     |  10 --
 R/methods_multcomp.R      |   6 --
 R/methods_nestedLogit.R   |  34 ------
 R/methods_nlme.R          |   6 --
 R/methods_other.R         |   7 --
 R/methods_plm.R           |   9 --
 R/methods_quantreg.R      |  33 ------
 R/methods_selection.R     |   8 --
 R/methods_serp.R          |  14 ---
 R/methods_survey.R        |   2 +-
 R/methods_svy2lme.R       |   6 --
 R/methods_systemfit.R     |  22 ----
 R/methods_truncreg.R      |   4 -
 R/methods_tseries.R       |   4 -
 R/methods_vgam.R          |  11 +-
 man/degrees_of_freedom.Rd |  19 ++--
 43 files changed, 85 insertions(+), 834 deletions(-)
 delete mode 100644 R/methods_serp.R
 delete mode 100644 R/methods_tseries.R

diff --git a/NAMESPACE b/NAMESPACE
index 1bfa0c66b..0b725c334 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -118,62 +118,6 @@ S3method(convert_efa_to_cfa,fa)
 S3method(convert_efa_to_cfa,fa.ci)
 S3method(convert_efa_to_cfa,parameters_efa)
 S3method(convert_efa_to_cfa,parameters_pca)
-S3method(degrees_of_freedom,BBmm)
-S3method(degrees_of_freedom,BBreg)
-S3method(degrees_of_freedom,betamfx)
-S3method(degrees_of_freedom,betaor)
-S3method(degrees_of_freedom,bfsl)
-S3method(degrees_of_freedom,bigglm)
-S3method(degrees_of_freedom,biglm)
-S3method(degrees_of_freedom,cgam)
-S3method(degrees_of_freedom,cgamm)
-S3method(degrees_of_freedom,coeftest)
-S3method(degrees_of_freedom,complmrob)
-S3method(degrees_of_freedom,default)
-S3method(degrees_of_freedom,emmGrid)
-S3method(degrees_of_freedom,emm_list)
-S3method(degrees_of_freedom,fixest)
-S3method(degrees_of_freedom,fixest_multi)
-S3method(degrees_of_freedom,garch)
-S3method(degrees_of_freedom,glht)
-S3method(degrees_of_freedom,gls)
-S3method(degrees_of_freedom,hglm)
-S3method(degrees_of_freedom,ivFixed)
-S3method(degrees_of_freedom,ivprobit)
-S3method(degrees_of_freedom,logitmfx)
-S3method(degrees_of_freedom,logitor)
-S3method(degrees_of_freedom,lqm)
-S3method(degrees_of_freedom,lqmm)
-S3method(degrees_of_freedom,mediate)
-S3method(degrees_of_freedom,merModList)
-S3method(degrees_of_freedom,mhurdle)
-S3method(degrees_of_freedom,mipo)
-S3method(degrees_of_freedom,mira)
-S3method(degrees_of_freedom,mmrm)
-S3method(degrees_of_freedom,mmrm_fit)
-S3method(degrees_of_freedom,mmrm_tmb)
-S3method(degrees_of_freedom,model_fit)
-S3method(degrees_of_freedom,multinom)
-S3method(degrees_of_freedom,negbinirr)
-S3method(degrees_of_freedom,negbinmfx)
-S3method(degrees_of_freedom,nestedLogit)
-S3method(degrees_of_freedom,nlrq)
-S3method(degrees_of_freedom,nnet)
-S3method(degrees_of_freedom,plm)
-S3method(degrees_of_freedom,poissonirr)
-S3method(degrees_of_freedom,poissonmfx)
-S3method(degrees_of_freedom,probitmfx)
-S3method(degrees_of_freedom,rlm)
-S3method(degrees_of_freedom,rq)
-S3method(degrees_of_freedom,rqs)
-S3method(degrees_of_freedom,rqss)
-S3method(degrees_of_freedom,selection)
-S3method(degrees_of_freedom,serp)
-S3method(degrees_of_freedom,summary.lm)
-S3method(degrees_of_freedom,svy2lme)
-S3method(degrees_of_freedom,systemfit)
-S3method(degrees_of_freedom,truncreg)
-S3method(degrees_of_freedom,vgam)
 S3method(display,compare_parameters)
 S3method(display,equivalence_test_lm)
 S3method(display,parameters_brms_meta)
diff --git a/R/compare_parameters.R b/R/compare_parameters.R
index 05305e244..2f03e4576 100644
--- a/R/compare_parameters.R
+++ b/R/compare_parameters.R
@@ -310,3 +310,19 @@ compare_models <- compare_parameters
 
   x
 }
+
+
+.is_bayesian_model <- function(x, exclude = NULL) {
+  bayes_classes <- c(
+    "brmsfit", "stanfit", "MCMCglmm", "stanreg",
+    "stanmvreg", "bmerMod", "BFBayesFactor", "bamlss",
+    "bayesx", "mcmc", "bcplm", "bayesQR", "BGGM",
+    "meta_random", "meta_fixed", "meta_bma", "blavaan",
+    "blrm", "blmerMod"
+  )
+  # if exclude is not NULL, remove elements in exclude from bayes_class
+  if (!is.null(exclude)) {
+    bayes_classes <- bayes_classes[!bayes_classes %in% exclude]
+  }
+  inherits(x, bayes_classes)
+}
diff --git a/R/dof.R b/R/dof.R
index f0848eb2c..022a61501 100644
--- a/R/dof.R
+++ b/R/dof.R
@@ -47,17 +47,15 @@
 #' `"satterthwaite"`, each model parameter can have a different degree of
 #' freedom.
 #'
-#' @examples
+#' @examplesIf require("lme4", quietly = TRUE)
 #' model <- lm(Sepal.Length ~ Petal.Length * Species, data = iris)
 #' dof(model)
 #'
 #' model <- glm(vs ~ mpg * cyl, data = mtcars, family = "binomial")
 #' dof(model)
 #' \donttest{
-#' if (require("lme4", quietly = TRUE)) {
-#'   model <- lmer(Sepal.Length ~ Petal.Length + (1 | Species), data = iris)
-#'   dof(model)
-#' }
+#' model <- lmer(Sepal.Length ~ Petal.Length + (1 | Species), data = iris)
+#' dof(model)
 #'
 #' if (require("rstanarm", quietly = TRUE)) {
 #'   model <- stan_glm(
@@ -70,84 +68,8 @@
 #' }
 #' }
 #' @export
-degrees_of_freedom <- function(model, ...) {
-  UseMethod("degrees_of_freedom")
-}
-
-
-
-
-#' @rdname degrees_of_freedom
-#' @export
-degrees_of_freedom.default <- function(model, method = "analytical", ...) {
-  # check for valid input
-  .is_model_valid(model)
-
-  if (is.null(method)) {
-    method <- "wald"
-  }
-  method <- tolower(method)
-
-  method <- match.arg(method, choices = c(
-    "analytical", "any", "fit", "ml1", "betwithin", "satterthwaite", "kenward",
-    "nokr", "wald", "kr", "profile", "boot", "uniroot", "residual", "normal",
-    "likelihood"
-  ))
-
-  if (!.dof_method_ok(model, method, ...) || method %in% c("profile", "likelihood", "boot", "uniroot")) {
-    method <- "any"
-  }
-
-  stat <- insight::find_statistic(model)
-
-  # for z-statistic, always return Inf
-  if (!is.null(stat) && stat == "z-statistic" && !(method %in% c("ml1", "betwithin"))) {
-    if (method == "residual") {
-      return(.degrees_of_freedom_residual(model, verbose = FALSE))
-    } else {
-      return(Inf)
-    }
-  }
-
-  # Chi2-distributions usually have 1 df
-  if (!is.null(stat) && stat == "chi-squared statistic") {
-    if (method == "residual") {
-      return(.degrees_of_freedom_residual(model, verbose = FALSE))
-    } else {
-      return(1)
-    }
-  }
-
-  if (method == "any") { # nolint
-    dof <- .degrees_of_freedom_residual(model, verbose = FALSE)
-    if (is.null(dof) || all(is.infinite(dof)) || anyNA(dof)) {
-      dof <- .degrees_of_freedom_analytical(model, kenward = FALSE)
-    }
-  } else if (method == "ml1") {
-    dof <- dof_ml1(model)
-  } else if (method == "wald") {
-    dof <- .degrees_of_freedom_residual(model, verbose = FALSE)
-  } else if (method == "normal") {
-    dof <- Inf
-  } else if (method == "satterthwaite") {
-    dof <- dof_satterthwaite(model)
-  } else if (method == "betwithin") {
-    dof <- dof_betwithin(model)
-  } else if (method %in% c("kenward", "kr")) {
-    dof <- dof_kenward(model)
-  } else if (method == "analytical") {
-    dof <- .degrees_of_freedom_analytical(model, kenward = TRUE)
-  } else if (method == "nokr") {
-    dof <- .degrees_of_freedom_analytical(model, kenward = FALSE)
-  } else {
-    dof <- .degrees_of_freedom_residual(model)
-  }
-
-  if (!is.null(dof) && length(dof) > 0 && all(dof == 0)) {
-    insight::format_warning("Model has zero degrees of freedom!")
-  }
-
-  dof
+degrees_of_freedom <- function(model, method = "analytical", ...) {
+  insight::get_df(x = model, type = method, ...)
 }
 
 #' @rdname degrees_of_freedom
@@ -155,110 +77,6 @@ degrees_of_freedom.default <- function(model, method = "analytical", ...) {
 dof <- degrees_of_freedom
 
 
-
-
-
-# Analytical approach ------------------------------
-
-
-#' @keywords internal
-.degrees_of_freedom_analytical <- function(model, kenward = TRUE) {
-  nparam <- n_parameters(model)
-  n <- insight::n_obs(model)
-
-  if (is.null(n)) {
-    n <- Inf
-  }
-
-  if (isTRUE(kenward) && inherits(model, "lmerMod")) {
-    dof <- as.numeric(dof_kenward(model))
-  } else {
-    dof <- rep(n - nparam, nparam)
-  }
-
-  dof
-}
-
-
-
-
-
-# Model approach (Residual df) ------------------------------
-
-
-#' @keywords internal
-.degrees_of_freedom_residual <- function(model, verbose = TRUE) {
-  if (.is_bayesian_model(model, exclude = c("bmerMod", "bayesx", "blmerMod", "bglmerMod"))) {
-    model <- bayestestR::bayesian_as_frequentist(model)
-  }
-
-  # 1st try
-  dof <- try(stats::df.residual(model), silent = TRUE)
-
-  # 2nd try
-  if (inherits(dof, "try-error") || is.null(dof) || all(is.na(dof))) {
-    junk <- utils::capture.output(dof = try(summary(model)$df[2], silent = TRUE))
-  }
-
-  # 3rd try, nlme
-  if (inherits(dof, "try-error") || is.null(dof) || all(is.na(dof))) {
-    dof <- try(unname(model$fixDF$X), silent = TRUE)
-  }
-
-  # last try
-  if (inherits(dof, "try-error") || is.null(dof) || all(is.na(dof))) {
-    dof <- Inf
-    if (verbose) {
-      insight::format_alert("Could not extract degrees of freedom.")
-    }
-  }
-
-
-  # special cases
-  # if (inherits(model, "gam")) {
-  #   dof <- .dof_fit_gam(model, dof)
-  # }
-
-  dof
-}
-
-
-
-
-# residual df - for models with residual df, but no "df.residual()" method --------------
-
-
-#' @keywords internal
-.degrees_of_freedom_no_dfresid_method <- function(model, method = NULL) {
-  if (identical(method, "normal")) {
-    return(Inf)
-  } else if (!is.null(method) && method %in% c("ml1", "satterthwaite", "betwithin")) {
-    degrees_of_freedom.default(model, method = method)
-  } else {
-    .degrees_of_freedom_analytical(model, kenward = FALSE)
-  }
-}
-
-
-
-
-
-
-# helper --------------
-
-.dof_fit_gam <- function(model, dof) {
-  params <- insight::find_parameters(model)
-  if (!is.null(params$conditional)) {
-    dof <- rep(dof, length(params$conditional))
-  }
-  if (!is.null(params$smooth_terms)) {
-    s <- summary(model)
-    dof <- c(dof, s$s.table[, "Ref.df"])
-  }
-  dof
-}
-
-
 # Helper, check args ------------------------------
 
 .dof_method_ok <- function(model, method, type = "df_method", verbose = TRUE, ...) {
@@ -329,23 +147,3 @@ dof <- degrees_of_freedom
 
   return(TRUE)
 }
-
-
-
-
-# helper
-
-.is_bayesian_model <- function(x, exclude = NULL) {
-  bayes_classes <- c(
-    "brmsfit", "stanfit", "MCMCglmm", "stanreg",
-    "stanmvreg", "bmerMod", "BFBayesFactor", "bamlss",
-    "bayesx", "mcmc", "bcplm", "bayesQR", "BGGM",
-    "meta_random", "meta_fixed", "meta_bma", "blavaan",
-    "blrm", "blmerMod"
-  )
-  # if exclude is not NULL, remove elements in exclude from bayes_class
-  if (!is.null(exclude)) {
-    bayes_classes <- bayes_classes[!bayes_classes %in% exclude]
-  }
-  inherits(x, bayes_classes)
-}
diff --git a/R/extract_parameters.R b/R/extract_parameters.R
index 473036b2d..3696ec4de 100644
--- a/R/extract_parameters.R
+++ b/R/extract_parameters.R
@@ -318,7 +318,7 @@
     sig <- .safe(suppressWarnings(insight::get_sigma(model, ci = NULL, verbose = FALSE)))
     attr(params, "sigma") <- as.numeric(sig)
 
-    resdf <- .safe(suppressWarnings(insight::get_df(model, type = "residual")))
+    resdf <- .safe(suppressWarnings(insight::get_df(x = model, type = "residual")))
     attr(params, "residual_df") <- as.numeric(resdf)
   }
   params
diff --git a/R/methods_BBMM.R b/R/methods_BBMM.R
index 912b16b0c..15ae03155 100644
--- a/R/methods_BBMM.R
+++ b/R/methods_BBMM.R
@@ -64,18 +64,3 @@ p_value.BBreg <- function(model, ...) {
     p = as.data.frame(summary(model)$coefficients)$p.value
   )
 }
-
-
-
-#' @export
-degrees_of_freedom.BBmm <- function(model, method = "residual", ...) {
-  if (method %in% c("residual", "wald")) {
-    return(model$df)
-  } else {
-    return(degrees_of_freedom.default(model = model, method = method, ...))
-  }
-}
-
-
-#' @export
-degrees_of_freedom.BBreg <- degrees_of_freedom.BBmm
diff --git a/R/methods_bfsl.R b/R/methods_bfsl.R
index 5297e0632..078946cd3 100644
--- a/R/methods_bfsl.R
+++ b/R/methods_bfsl.R
@@ -37,20 +37,3 @@ standard_error.bfsl <- function(model, ...) {
   )
   insight::text_remove_backticks(params, verbose = FALSE)
 }
-
-
-
-#' @export
-degrees_of_freedom.bfsl <- function(model, method = "residual", ...) {
-  if (is.null(method)) {
-    method <- "wald"
-  }
-
-  method <- match.arg(tolower(method), choices = c("analytical", "any", "fit", "wald", "residual", "normal"))
-
-  if (method %in% c("wald", "residual", "fit")) {
-    model$df.residual
-  } else {
-    degrees_of_freedom.default(model, method = method, ...)
-  }
-}
diff --git a/R/methods_biglm.R b/R/methods_biglm.R
index 56454116a..ddb9e47a1 100644
--- a/R/methods_biglm.R
+++ b/R/methods_biglm.R
@@ -8,12 +8,3 @@ standard_error.biglm <- function(model, ...) {
     SE = as.vector(cs[, 4])
   )
 }
-
-
-#' @export
-degrees_of_freedom.biglm <- function(model, method = NULL, ...) {
-  .degrees_of_freedom_no_dfresid_method(model, method)
-}
-
-#' @export
-degrees_of_freedom.bigglm <- degrees_of_freedom.biglm
diff --git a/R/methods_brglm2.R b/R/methods_brglm2.R
index 2b9eb4ca9..e4f0bc983 100644
--- a/R/methods_brglm2.R
+++ b/R/methods_brglm2.R
@@ -181,19 +181,6 @@ ci.multinom <- function(x, ci = 0.95, method = "normal", verbose = TRUE, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.multinom <- function(model, method = NULL, ...) {
-  if (is.null(method) || identical(method, "normal")) {
-    Inf
-  } else {
-    insight::n_obs(model) - model$edf
-  }
-}
-
-#' @export
-degrees_of_freedom.nnet <- degrees_of_freedom.multinom
-
-
 #' @export
 standard_error.multinom <- function(model, ...) {
   se <- tryCatch(
diff --git a/R/methods_cgam.R b/R/methods_cgam.R
index a70416cd2..0204efa0f 100644
--- a/R/methods_cgam.R
+++ b/R/methods_cgam.R
@@ -166,38 +166,3 @@ standard_error.cgam <- function(model, ...) {
     Component = params$Component
   )
 }
-
-
-#' @export
-degrees_of_freedom.cgam <- function(model, method = "wald", ...) {
-  if (is.null(method)) {
-    method <- "wald"
-  }
-  method <- match.arg(tolower(method), choices = c("analytical", "any", "fit", "wald", "residual", "normal"))
-
-  if (method %in% c("wald", "residual", "fit")) {
-    stats::df.residual(model)
-  } else {
-    degrees_of_freedom.default(model, method = method, ...)
-  }
-}
-
-
-#' @export
-degrees_of_freedom.cgamm <- function(model, method = "wald", ...) {
-  if (is.null(method)) {
-    method <- "wald"
-  }
-  method <- match.arg(tolower(method), choices = c("analytical", "any", "fit", "wald", "residual", "normal"))
-
-  if (method %in% c("wald", "residual", "fit")) {
-    dof <- model$resid_df_obs
-    if (is.null(dof)) {
-      dof <- degrees_of_freedom.default(model, method = method, ...)
-    }
-  } else {
-    dof <- degrees_of_freedom.default(model, method = method, ...)
-  }
-
-  dof
-}
diff --git a/R/methods_effect_size.R b/R/methods_effect_size.R
index 579477b25..06896670c 100644
--- a/R/methods_effect_size.R
+++ b/R/methods_effect_size.R
@@ -17,21 +17,21 @@ ci.parameters_standardized <- function(x, ci = 0.95, verbose = TRUE, ...) {
   # check if we have model. if so, use df from model
   model <- .get_object(x)
   if (!is.null(model)) {
-    df <- degrees_of_freedom(model, method = "any")
-    if (!is.null(df)) {
-      if (length(df) > 1 && length(df) != nrow(x)) {
-        df <- Inf
+    dof <- insight::get_df(model, type = "wald")
+    if (!is.null(dof)) {
+      if (length(dof) > 1 && length(dof) != nrow(x)) {
+        dof <- Inf
       }
     } else {
-      df <- Inf
+      dof <- Inf
     }
   } else {
-    df <- Inf
+    dof <- Inf
   }
 
   out <- lapply(ci, function(i) {
     alpha <- (1 + i) / 2
-    fac <- stats::qt(alpha, df = df)
+    fac <- stats::qt(alpha, df = dof)
     data.frame(
       Parameter = x$Parameter,
       CI = i,
diff --git a/R/methods_emmeans.R b/R/methods_emmeans.R
index 0c5e1bb84..aac0f08dd 100644
--- a/R/methods_emmeans.R
+++ b/R/methods_emmeans.R
@@ -27,23 +27,7 @@ model_parameters.emmGrid <- function(model,
   s <- summary(model, level = ci, adjust = "none")
   params <- as.data.frame(s)
 
-  # we assume frequentist here...
-  if (!.is_bayesian_emmeans(model)) {
-    # get statistic, se and p
-    statistic <- insight::get_statistic(model, ci = ci, adjust = "none")
-    SE <- standard_error(model)
-    p <- p_value(model, ci = ci, adjust = "none")
-
-    params$Statistic <- statistic$Statistic
-    params$SE <- SE$SE
-    params$p <- p$p
-
-    # ==== adjust p-values?
-
-    if (!is.null(p_adjust)) {
-      params <- .p_adjust(params, p_adjust, model, verbose)
-    }
-  } else {
+  if (.is_bayesian_emmeans(model)) {
     # Bayesian models go here...
     params <- bayestestR::describe_posterior(
       model,
@@ -60,8 +44,22 @@ model_parameters.emmGrid <- function(model,
       verbose = verbose,
       ...
     )
-
     statistic <- NULL
+  } else {
+    # we assume frequentist here...
+    statistic <- insight::get_statistic(model, ci = ci, adjust = "none")
+    SE <- standard_error(model)
+    p <- p_value(model, ci = ci, adjust = "none")
+
+    params$Statistic <- statistic$Statistic
+    params$SE <- SE$SE
+    params$p <- p$p
+
+    # ==== adjust p-values?
+
+    if (!is.null(p_adjust)) {
+      params <- .p_adjust(params, p_adjust, model, verbose)
+    }
   }
 
 
@@ -88,11 +86,11 @@ model_parameters.emmGrid <- function(model,
   if (!any(startsWith(colnames(params), "CI_"))) {
     df_column <- grep("(df|df_error)", colnames(params))
     if (length(df_column) > 0) {
-      df <- params[[df_column[1]]]
+      dof <- params[[df_column[1]]]
     } else {
-      df <- Inf
+      dof <- Inf
     }
-    fac <- stats::qt((1 + ci) / 2, df = df)
+    fac <- stats::qt((1 + ci) / 2, df = dof)
     params$CI_low <- params$Estimate - fac * params$SE
     params$CI_high <- params$Estimate + fac * params$SE
   }
@@ -105,12 +103,12 @@ model_parameters.emmGrid <- function(model,
   # Reorder
   estimate_pos <- which(colnames(s) == estName)
   parameter_names <- colnames(params)[seq_len(estimate_pos - 1)]
-  order <- c(
+  col_order <- c(
     parameter_names, "Estimate", "Median", "Mean", "SE", "SD", "MAD",
     "CI_low", "CI_high", "F", "t", "z", "df", "df_error", "p", "pd",
     "ROPE_CI", "ROPE_low", "ROPE_high", "ROPE_Percentage"
   )
-  params <- params[order[order %in% names(params)]]
+  params <- params[col_order[col_order %in% names(params)]]
 
   # rename
   names(params) <- gsub("Estimate", "Coefficient", names(params), fixed = TRUE)
@@ -210,12 +208,12 @@ model_parameters.summary_emm <- function(model,
   # Reorder
   estimate_pos <- which(colnames(model) == estName)
   parameter_names <- colnames(params)[seq_len(estimate_pos - 1)]
-  order <- c(
+  col_order <- c(
     parameter_names, "Estimate", "Median", "Mean", "SE", "SD", "MAD",
     "CI_low", "CI_high", "F", "t", "z", "df", "df_error", "p", "pd",
     "ROPE_CI", "ROPE_low", "ROPE_high", "ROPE_Percentage"
   )
-  params <- params[order[order %in% names(params)]]
+  params <- params[col_order[col_order %in% names(params)]]
 
   # rename
   names(params) <- gsub("Estimate", "Coefficient", names(params), fixed = TRUE)
@@ -315,42 +313,6 @@ boot_em_standard_error <- function(model) {
 
 
 
-
-# degrees of freedom --------------------
-
-
-#' @export
-degrees_of_freedom.emmGrid <- function(model, ...) {
-  if (!is.null(model@misc$is_boot) && model@misc$is_boot) {
-    return(boot_em_df(model))
-  }
-
-  summary(model)$df
-}
-
-
-#' @export
-degrees_of_freedom.emm_list <- function(model, ...) {
-  if (!is.null(model[[1]]@misc$is_boot) && model[[1]]@misc$is_boot) {
-    return(boot_em_df(model))
-  }
-
-  s <- summary(model)
-  unlist(lapply(s, function(i) {
-    if (is.null(i$df)) {
-      rep(Inf, nrow(i))
-    } else {
-      i$df
-    }
-  }), use.names = FALSE)
-}
-
-boot_em_df <- function(model) {
-  est <- insight::get_parameters(model, summary = FALSE)
-  rep(NA, ncol(est))
-}
-
-
 # p values ----------------------
 
 
@@ -361,21 +323,20 @@ p_value.emmGrid <- function(model, ci = 0.95, adjust = "none", ...) {
     return(boot_em_pval(model, adjust))
   }
 
-
   s <- summary(model, level = ci, adjust = adjust)
   estimate_pos <- which(colnames(s) == attr(s, "estName"))
 
-  if (length(estimate_pos)) {
-    stat <- insight::get_statistic(model, ci = ci, adjust = adjust)
-    p <- 2 * stats::pt(abs(stat$Statistic), df = s$df, lower.tail = FALSE)
-
-    .data_frame(
-      Parameter = .pretty_emmeans_Parameter_names(model),
-      p = as.vector(p)
-    )
-  } else {
+  if (!length(estimate_pos)) {
     return(NULL)
   }
+
+  stat <- insight::get_statistic(model, ci = ci, adjust = adjust)
+  p <- 2 * stats::pt(abs(stat$Statistic), df = s$df, lower.tail = FALSE)
+
+  .data_frame(
+    Parameter = .pretty_emmeans_Parameter_names(model),
+    p = as.vector(p)
+  )
 }
 
 
@@ -418,8 +379,8 @@ p_value.emm_list <- function(model, adjust = "none", ...) {
 
     # test statistic and p-values
     stat <- params$Estimate / se
-    df <- degrees_of_freedom(model)
-    p_val <- 2 * stats::pt(abs(stat), df = df, lower.tail = FALSE)
+    dof <- insight::get_df(model)
+    p_val <- 2 * stats::pt(abs(stat), df = dof, lower.tail = FALSE)
     out$p[is.na(out$p)] <- p_val[is.na(out$p)]
   }
 
diff --git a/R/methods_fixest.R b/R/methods_fixest.R
index bb2a04d17..9481f0090 100644
--- a/R/methods_fixest.R
+++ b/R/methods_fixest.R
@@ -82,34 +82,6 @@ standard_error.fixest <- function(model, vcov = NULL, vcov_args = NULL, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.fixest <- function(model, method = "wald", ...) {
-  # fixest degrees of freedom can be tricky. best to use the function by the
-  # package.
-  insight::check_if_installed("fixest")
-  if (is.null(method)) {
-    method <- "wald"
-  }
-  method <- match.arg(
-    tolower(method),
-    choices = c("wald", "residual", "normal")
-  )
-
-  # we may have Inf DF, too
-  if (method == "normal") {
-    return(Inf)
-  }
-
-  method <- switch(method,
-    wald = "t",
-    residual = "resid"
-  )
-  fixest::degrees_freedom(model, type = method)
-}
-
-
-
-
 # .feglm -----------------------
 
 #' @export
@@ -226,22 +198,6 @@ standard_error.fixest_multi <- function(model, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.fixest_multi <- function(model, ...) {
-  out <- do.call(rbind, lapply(model, degrees_of_freedom, ...))
-
-  # add response and group columns
-  id_columns <- .get_fixest_multi_columns(model)
-
-  # add response column
-  out$Response <- id_columns$Response
-  out$Group <- id_columns$Group
-
-  row.names(out) <- NULL
-  out
-}
-
-
 #' @export
 p_value.fixest_multi <- function(model, ...) {
   out <- do.call(rbind, lapply(model, p_value, ...))
diff --git a/R/methods_gee.R b/R/methods_gee.R
index 3b173b8f9..9dcaa3b65 100644
--- a/R/methods_gee.R
+++ b/R/methods_gee.R
@@ -56,7 +56,7 @@ p_value.geeglm <- function(model, method = "wald", ...) {
 
   if (!is.null(stat)) {
     if (identical(method, "residual")) {
-      dof <- degrees_of_freedom(model, method = "residual")
+      dof <- insight::get_df(model, type = "residual")
       p <- as.vector(2 * stats::pt(
         sqrt(abs(stat$Statistic)),
         df = dof,
diff --git a/R/methods_hglm.R b/R/methods_hglm.R
index 4f237e112..c324d3d4f 100644
--- a/R/methods_hglm.R
+++ b/R/methods_hglm.R
@@ -154,15 +154,6 @@ standard_error.hglm <- function(model,
 }
 
 
-#' @export
-degrees_of_freedom.hglm <- function(model, method = "residual", ...) {
-  if (method == "any") {
-    method <- "residual"
-  }
-  insight::get_df(model, type = method, ...)
-}
-
-
 #' @export
 ci.hglm <- function(x,
                     ci = 0.95,
diff --git a/R/methods_ivfixed.R b/R/methods_ivfixed.R
index 6c175646c..25cb92734 100644
--- a/R/methods_ivfixed.R
+++ b/R/methods_ivfixed.R
@@ -6,28 +6,17 @@ ci.ivFixed <- ci.default
 standard_error.ivFixed <- standard_error.coxr
 
 
-#' @export
-degrees_of_freedom.ivFixed <- function(model, method = "wald", ...) {
-  if (is.null(method)) {
-    method <- "wald"
-  }
-  method <- match.arg(tolower(method), choices = c("analytical", "any", "fit", "wald", "residual", "normal"))
-
-  if (method %in% c("wald", "residual", "fit")) {
-    as.vector(model$df)
-  } else {
-    degrees_of_freedom.default(model, method = method, ...)
-  }
-}
-
-
 #' @export
 p_value.ivFixed <- function(model, method = "wald", ...) {
   stat <- insight::get_statistic(model)
   if (!is.null(stat)) {
     .data_frame(
       Parameter = stat$Parameter,
-      p = as.vector(2 * stats::pt(abs(stat$Statistic), df = degrees_of_freedom(model, method = method), lower.tail = FALSE))
+      p = as.vector(2 * stats::pt(
+        abs(stat$Statistic),
+        df = insight::get_df(model, type = method),
+        lower.tail = FALSE
+      ))
     )
   }
 }
diff --git a/R/methods_ivprobit.R b/R/methods_ivprobit.R
index 826719b71..d2fe1cec4 100644
--- a/R/methods_ivprobit.R
+++ b/R/methods_ivprobit.R
@@ -2,11 +2,6 @@
 ci.ivprobit <- ci.default
 
 
-
-#' @export
-degrees_of_freedom.ivprobit <- degrees_of_freedom.ivFixed
-
-
 #' @export
 standard_error.ivprobit <- function(model, ...) {
   .data_frame(
diff --git a/R/methods_lm.R b/R/methods_lm.R
index a52ad3d87..42c13e0d5 100644
--- a/R/methods_lm.R
+++ b/R/methods_lm.R
@@ -47,9 +47,3 @@ p_value.summary.lm <- function(model, ...) {
 ci.summary.lm <- function(x, ci = 0.95, method = "residual", ...) {
   .ci_generic(model = x, ci = ci, method = method, dof = insight::get_df(x), ...)
 }
-
-
-#' @export
-degrees_of_freedom.summary.lm <- function(model, ...) {
-  model$fstatistic[3]
-}
diff --git a/R/methods_lmtest.R b/R/methods_lmtest.R
index c73d0a528..3809572e2 100644
--- a/R/methods_lmtest.R
+++ b/R/methods_lmtest.R
@@ -1,8 +1,3 @@
-#' @export
-degrees_of_freedom.coeftest <- function(model, ...) {
-  attributes(model)$df
-}
-
 #' @export
 ci.coeftest <- ci.default
 
diff --git a/R/methods_lqmm.R b/R/methods_lqmm.R
index 5b3c8ecae..108af5274 100644
--- a/R/methods_lqmm.R
+++ b/R/methods_lqmm.R
@@ -67,17 +67,6 @@ standard_error.lqmm <- function(model, ...) {
 standard_error.lqm <- standard_error.lqmm
 
 
-#' @export
-degrees_of_freedom.lqmm <- function(model, ...) {
-  out <- model_parameters(model, ...)
-  out$df_error
-}
-
-
-#' @export
-degrees_of_freedom.lqm <- degrees_of_freedom.lqmm
-
-
 #' @export
 p_value.lqmm <- function(model, ...) {
   out <- model_parameters(model, ...)
diff --git a/R/methods_lrm.R b/R/methods_lrm.R
index f919e0cb9..b5915fc4d 100644
--- a/R/methods_lrm.R
+++ b/R/methods_lrm.R
@@ -47,13 +47,13 @@ p_value.lrm <- function(model, ...) {
   # Issue: 697: typically the degrees of freedom are the same for every
   # observation, but the value is repeated. This poses problems in multiple
   # imputation models with Hmisc when we get more df values than parameters.
-  df <- degrees_of_freedom(model, method = "any")
-  dfu <- unique(df)
+  dof <- insight::get_df(model, type = "wald")
+  dfu <- unique(dof)
   if (length(dfu) == 1) {
-    df <- dfu
+    dof <- dfu
   }
 
-  p <- 2 * stats::pt(abs(stat$Statistic), df = df, lower.tail = FALSE)
+  p <- 2 * stats::pt(abs(stat$Statistic), df = dof, lower.tail = FALSE)
 
   .data_frame(
     Parameter = .remove_backticks_from_string(stat$Parameter),
diff --git a/R/methods_mass.R b/R/methods_mass.R
index 57804441d..7d1f54728 100644
--- a/R/methods_mass.R
+++ b/R/methods_mass.R
@@ -1,15 +1,3 @@
-# degrees of freedom -----------------
-
-#' @export
-degrees_of_freedom.rlm <- function(model, method = "residual", ...) {
-  .degrees_of_freedom_no_dfresid_method(model, method)
-}
-
-
-
-
-
-
 # ci -----------------
 
 #' @export
@@ -49,9 +37,6 @@ ci.polr <- function(x, ci = 0.95, dof = NULL, method = "profile", ...) {
 
 
 
-
-
-
 # SE -----------------
 
 #' @export
@@ -73,9 +58,6 @@ standard_error.polr <- function(model, method = NULL, ...) {
 
 
 
-
-
-
 # p -----------------
 
 #' @export
@@ -85,7 +67,7 @@ p_value.negbin <- p_value.default
 #' @export
 p_value.rlm <- function(model, ...) {
   cs <- stats::coef(summary(model))
-  p <- 2 * stats::pt(abs(cs[, 3]), df = degrees_of_freedom(model, method = "any"), lower.tail = FALSE)
+  p <- 2 * stats::pt(abs(cs[, 3]), df = insight::get_df(model, type = "wald"), lower.tail = FALSE)
   .data_frame(
     Parameter = .remove_backticks_from_string(names(p)),
     p = as.vector(p)
@@ -102,7 +84,7 @@ p_value.polr <- function(model, method = NULL, ...) {
 
   smry <- suppressMessages(as.data.frame(stats::coef(summary(model))))
   tstat <- smry[[3]]
-  p <- 2 * stats::pt(abs(tstat), df = degrees_of_freedom(model, method = "any"), lower.tail = FALSE)
+  p <- 2 * stats::pt(abs(tstat), df = insight::get_df(x = model, type = "wald"), lower.tail = FALSE)
   names(p) <- rownames(smry)
 
   .data_frame(
@@ -113,8 +95,6 @@ p_value.polr <- function(model, method = NULL, ...) {
 
 
 
-
-
 # parameters -----------------
 
 #' @rdname model_parameters.default
diff --git a/R/methods_mediate.R b/R/methods_mediate.R
index ef907a9ca..a728ecd6d 100644
--- a/R/methods_mediate.R
+++ b/R/methods_mediate.R
@@ -95,12 +95,6 @@ standard_error.mediate <- function(model, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.mediate <- function(model, ...) {
-  NULL
-}
-
-
 #' @export
 p_value.mediate <- function(model, ...) {
   info <- insight::model_info(model$model.y, verbose = FALSE)
diff --git a/R/methods_merTools.R b/R/methods_merTools.R
index c5f5ff060..4276c5a91 100644
--- a/R/methods_merTools.R
+++ b/R/methods_merTools.R
@@ -43,13 +43,6 @@ standard_error.merModList <- function(model, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.merModList <- function(model, ...) {
-  s <- suppressWarnings(summary(model))
-  s$fe$df
-}
-
-
 #' @export
 format_parameters.merModList <- function(model, brackets = c("[", "]"), ...) {
   .format_parameter_default(model[[1]], brackets = brackets)
diff --git a/R/methods_mfx.R b/R/methods_mfx.R
index 7709fb31d..847eb79a7 100644
--- a/R/methods_mfx.R
+++ b/R/methods_mfx.R
@@ -296,50 +296,6 @@ standard_error.betamfx <- function(model,
 
 
 
-
-# degrees of freedom ------------------
-
-
-#' @export
-degrees_of_freedom.logitor <- function(model, ...) {
-  degrees_of_freedom.default(model$fit, ...)
-}
-
-
-#' @export
-degrees_of_freedom.poissonirr <- degrees_of_freedom.logitor
-
-
-#' @export
-degrees_of_freedom.negbinirr <- degrees_of_freedom.logitor
-
-
-#' @export
-degrees_of_freedom.poissonmfx <- degrees_of_freedom.logitor
-
-
-#' @export
-degrees_of_freedom.logitmfx <- degrees_of_freedom.logitor
-
-
-#' @export
-degrees_of_freedom.negbinmfx <- degrees_of_freedom.logitor
-
-
-#' @export
-degrees_of_freedom.probitmfx <- degrees_of_freedom.logitor
-
-
-#' @export
-degrees_of_freedom.betaor <- degrees_of_freedom.logitor
-
-
-#' @export
-degrees_of_freedom.betamfx <- degrees_of_freedom.logitor
-
-
-
-
 # p values ------------------
 
 
diff --git a/R/methods_mhurdle.R b/R/methods_mhurdle.R
index a28befd11..47775b8c2 100644
--- a/R/methods_mhurdle.R
+++ b/R/methods_mhurdle.R
@@ -61,12 +61,6 @@ ci.mhurdle <- function(x, ci = 0.95, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.mhurdle <- function(model, method = NULL, ...) {
-  .degrees_of_freedom_no_dfresid_method(model, method)
-}
-
-
 #' @export
 standard_error.mhurdle <- function(model, component = c("all", "conditional", "zi", "zero_inflated", "infrequent_purchase", "ip", "auxiliary"), ...) {
   component <- match.arg(component)
diff --git a/R/methods_mice.R b/R/methods_mice.R
index 93b25ddfd..ecadff56c 100644
--- a/R/methods_mice.R
+++ b/R/methods_mice.R
@@ -11,21 +11,6 @@ ci.mira <- function(x, ci = 0.95, ...) {
 }
 
 
-# degrees of freedom ----------------------------
-
-#' @export
-degrees_of_freedom.mira <- function(model, ...) {
-  insight::check_if_installed("mice")
-  degrees_of_freedom(mice::pool(model), ...)
-}
-
-
-#' @export
-degrees_of_freedom.mipo <- function(model, ...) {
-  as.vector(summary(model)$df)
-}
-
-
 # p values ---------------------------------------
 
 #' @export
diff --git a/R/methods_mmrm.R b/R/methods_mmrm.R
index b97598df5..89b68b402 100644
--- a/R/methods_mmrm.R
+++ b/R/methods_mmrm.R
@@ -126,18 +126,3 @@ standard_error.mmrm_fit <- standard_error.mmrm
 
 #' @export
 standard_error.mmrm_tmb <- standard_error.mmrm
-
-
-# degrees of freedom ------------------
-
-#' @export
-degrees_of_freedom.mmrm <- function(model, ...) {
-  summary_table <- stats::coef(summary(model))
-  unname(summary_table[, "df"])
-}
-
-#' @export
-degrees_of_freedom.mmrm_fit <- degrees_of_freedom.mmrm
-
-#' @export
-degrees_of_freedom.mmrm_tmb <- degrees_of_freedom.mmrm
diff --git a/R/methods_model_fit.R b/R/methods_model_fit.R
index 1f02b2032..306a305a8 100644
--- a/R/methods_model_fit.R
+++ b/R/methods_model_fit.R
@@ -54,16 +54,6 @@ standard_error.model_fit <- function(model, ...) {
 
 
 
-# degrees of freedom ------------------
-
-
-#' @export
-degrees_of_freedom.model_fit <- function(model, ...) {
-  degrees_of_freedom(model$fit, ...)
-}
-
-
-
 # p values ------------------
 
 
diff --git a/R/methods_multcomp.R b/R/methods_multcomp.R
index f906c1560..963cc85d1 100644
--- a/R/methods_multcomp.R
+++ b/R/methods_multcomp.R
@@ -103,12 +103,6 @@ standard_error.glht <- function(model, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.glht <- function(model, ...) {
-  model$df
-}
-
-
 #' @export
 p_value.glht <- function(model, ...) {
   s <- summary(model)
diff --git a/R/methods_nestedLogit.R b/R/methods_nestedLogit.R
index 90bc86169..c87df18bd 100644
--- a/R/methods_nestedLogit.R
+++ b/R/methods_nestedLogit.R
@@ -75,40 +75,6 @@ model_parameters.nestedLogit <- function(model,
 }
 
 
-#' @export
-degrees_of_freedom.nestedLogit <- function(model,
-                                           method = NULL,
-                                           component = "all",
-                                           verbose = TRUE,
-                                           ...) {
-  if (is.null(method)) {
-    method <- "wald"
-  }
-  if (tolower(method) == "residual") {
-    cf <- as.data.frame(stats::coef(model))
-    dof <- rep(vapply(model$models, stats::df.residual, numeric(1)), each = nrow(cf))
-    if (!is.null(component) && !identical(component, "all")) {
-      comp <- intersect(names(dof), component)
-      if (length(comp)) {
-        dof <- dof[comp]
-      } else {
-        if (verbose) {
-          insight::format_alert(paste0(
-            "No matching model found. Possible values for `component` are ",
-            toString(paste0("'", names(model$models), "'")),
-            "."
-          ))
-        }
-        dof <- Inf
-      }
-    }
-  } else {
-    dof <- Inf
-  }
-  dof
-}
-
-
 #' @export
 standard_error.nestedLogit <- function(model,
                                        component = "all",
diff --git a/R/methods_nlme.R b/R/methods_nlme.R
index 5b23fc5e9..ecd99429d 100644
--- a/R/methods_nlme.R
+++ b/R/methods_nlme.R
@@ -97,9 +97,3 @@ standard_error.gls <- standard_error.default
 
 #' @export
 p_value.gls <- p_value.default
-
-
-#' @export
-degrees_of_freedom.gls <- function(model, method = NULL, ...) {
-  .degrees_of_freedom_no_dfresid_method(model, method)
-}
diff --git a/R/methods_other.R b/R/methods_other.R
index 402f29ab8..1da9fccef 100644
--- a/R/methods_other.R
+++ b/R/methods_other.R
@@ -20,13 +20,6 @@ p_value.complmrob <- p_value.default
 ci.complmrob <- ci.default
 
 
-#' @export
-degrees_of_freedom.complmrob <- function(model, method = "wald", ...) {
-  .degrees_of_freedom_no_dfresid_method(model, method)
-}
-
-
-
 
 
 ############# .Gam --------------
diff --git a/R/methods_plm.R b/R/methods_plm.R
index 12e2be790..271c9ee93 100644
--- a/R/methods_plm.R
+++ b/R/methods_plm.R
@@ -4,15 +4,6 @@
 # plm ---------------------------
 
 
-#' @export
-degrees_of_freedom.plm <- function(model, method = "wald", ...) {
-  if (identical(method, "normal")) {
-    return(Inf)
-  }
-  model$df.residual
-}
-
-
 #' @export
 standard_error.plm <- function(model, vcov = NULL, vcov_args = NULL, verbose = TRUE, ...) {
   dots <- list(...)
diff --git a/R/methods_quantreg.R b/R/methods_quantreg.R
index 9e61e68f7..bed08b33e 100644
--- a/R/methods_quantreg.R
+++ b/R/methods_quantreg.R
@@ -323,36 +323,3 @@ p_value.rqss <- function(model,
 
   p
 }
-
-
-
-
-# degrees of freedom ---------------------
-
-
-#' @export
-degrees_of_freedom.rqs <- function(model, ...) {
-  tryCatch(
-    {
-      s <- suppressWarnings(summary(model, covariance = TRUE))
-      cs <- lapply(s, function(i) i$rdf)
-      unique(unlist(cs))
-    },
-    error = function(e) {
-      NULL
-    }
-  )
-}
-
-
-
-#' @export
-degrees_of_freedom.rqss <- degrees_of_freedom.multinom
-
-
-#' @export
-degrees_of_freedom.rq <- degrees_of_freedom.rqs
-
-
-#' @export
-degrees_of_freedom.nlrq <- degrees_of_freedom.mhurdle
diff --git a/R/methods_selection.R b/R/methods_selection.R
index 81582060b..46c227832 100644
--- a/R/methods_selection.R
+++ b/R/methods_selection.R
@@ -83,7 +83,6 @@ standard_error.selection <- function(model, component = c("all", "selection", "o
 }
 
 
-
 #' @export
 simulate_model.selection <- function(model,
                                      iterations = 1000,
@@ -100,10 +99,3 @@ simulate_model.selection <- function(model,
 
 #' @export
 ci.selection <- ci.default
-
-
-#' @export
-degrees_of_freedom.selection <- function(model, ...) {
-  s <- summary(model)
-  s$param$df
-}
diff --git a/R/methods_serp.R b/R/methods_serp.R
deleted file mode 100644
index c4f0fff71..000000000
--- a/R/methods_serp.R
+++ /dev/null
@@ -1,14 +0,0 @@
-#' @export
-degrees_of_freedom.serp <- function(model, method = "normal", ...) {
-  if (is.null(method)) {
-    method <- "wald"
-  }
-
-  method <- match.arg(tolower(method), choices = c("analytical", "any", "fit", "wald", "residual", "normal"))
-
-  if (method %in% c("residual", "fit")) {
-    model$rdf
-  } else {
-    degrees_of_freedom.default(model, method = method, ...)
-  }
-}
diff --git a/R/methods_survey.R b/R/methods_survey.R
index 04674bf8f..4af36e799 100644
--- a/R/methods_survey.R
+++ b/R/methods_survey.R
@@ -141,7 +141,7 @@ p_value.svyglm.nb <- function(model, ...) {
 
   est <- stats::coef(model)
   se <- sqrt(diag(stats::vcov(model, stderr = "robust")))
-  p <- 2 * stats::pt(abs(est / se), df = degrees_of_freedom(model, method = "any"), lower.tail = FALSE)
+  p <- 2 * stats::pt(abs(est / se), df = insight::get_df(model, type = "wald"), lower.tail = FALSE)
 
   .data_frame(
     Parameter = .remove_backticks_from_string(names(p)),
diff --git a/R/methods_svy2lme.R b/R/methods_svy2lme.R
index 90899b91a..e34e7bb88 100644
--- a/R/methods_svy2lme.R
+++ b/R/methods_svy2lme.R
@@ -105,9 +105,3 @@ p_value.svy2lme <- function(model, ...) {
     p = as.vector(p)
   )
 }
-
-
-#' @export
-degrees_of_freedom.svy2lme <- function(model, ...) {
-  Inf
-}
diff --git a/R/methods_systemfit.R b/R/methods_systemfit.R
index 166340c3b..9edd008de 100644
--- a/R/methods_systemfit.R
+++ b/R/methods_systemfit.R
@@ -33,7 +33,6 @@ model_parameters.systemfit <- function(model,
 }
 
 
-
 #' @export
 standard_error.systemfit <- function(model, ...) {
   cf <- stats::coef(summary(model))
@@ -57,7 +56,6 @@ standard_error.systemfit <- function(model, ...) {
 }
 
 
-
 #' @export
 p_value.systemfit <- function(model, ...) {
   cf <- stats::coef(summary(model))
@@ -81,25 +79,5 @@ p_value.systemfit <- function(model, ...) {
 }
 
 
-
-#' @export
-degrees_of_freedom.systemfit <- function(model, ...) {
-  dof <- NULL
-  s <- summary(model)$eq
-  params <- insight::find_parameters(model)
-  f <- insight::find_formula(model)
-  system_names <- names(f)
-
-  for (i in seq_along(system_names)) {
-    dfs <- rep(s[[i]]$df[2], length(params[[i]]))
-    df_names <- rep(names(params[i]), length(params[[i]]))
-    dof <- c(dof, stats::setNames(dfs, df_names))
-  }
-
-  dof
-}
-
-
-
 #' @export
 ci.systemfit <- ci.lm
diff --git a/R/methods_truncreg.R b/R/methods_truncreg.R
index dd260b243..ca04cd950 100644
--- a/R/methods_truncreg.R
+++ b/R/methods_truncreg.R
@@ -7,7 +7,3 @@ standard_error.truncreg <- standard_error.default
 
 #' @export
 p_value.truncreg <- p_value.default
-
-
-#' @export
-degrees_of_freedom.truncreg <- degrees_of_freedom.mhurdle
diff --git a/R/methods_tseries.R b/R/methods_tseries.R
deleted file mode 100644
index eefb3256d..000000000
--- a/R/methods_tseries.R
+++ /dev/null
@@ -1,4 +0,0 @@
-# classes: .garch
-
-#' @export
-degrees_of_freedom.garch <- degrees_of_freedom.mhurdle
diff --git a/R/methods_vgam.R b/R/methods_vgam.R
index 750189fac..a0018afdb 100644
--- a/R/methods_vgam.R
+++ b/R/methods_vgam.R
@@ -22,19 +22,10 @@ standard_error.vgam <- function(model, ...) {
 }
 
 
-#' @export
-degrees_of_freedom.vgam <- function(model, ...) {
-  params <- insight::get_parameters(model)
-  out <- stats::setNames(rep(NA, nrow(params)), params$Parameter)
-  out[names(model@nl.df)] <- model@nl.df
-  out
-}
-
-
 #' @export
 p_value.vgam <- function(model, ...) {
   stat <- insight::get_statistic(model)
-  stat$p <- as.vector(stats::pchisq(stat$Statistic, df = degrees_of_freedom(model), lower.tail = FALSE))
+  stat$p <- as.vector(stats::pchisq(stat$Statistic, df = insight::get_df(model), lower.tail = FALSE))
 
   stat[c("Parameter", "p", "Component")]
 }
diff --git a/man/degrees_of_freedom.Rd b/man/degrees_of_freedom.Rd
index 714ced31a..4d403f67b 100644
--- a/man/degrees_of_freedom.Rd
+++ b/man/degrees_of_freedom.Rd
@@ -2,21 +2,16 @@
 % Please edit documentation in R/dof.R
 \name{degrees_of_freedom}
 \alias{degrees_of_freedom}
-\alias{degrees_of_freedom.default}
 \alias{dof}
 \title{Degrees of Freedom (DoF)}
 \usage{
-degrees_of_freedom(model, ...)
+degrees_of_freedom(model, method = "analytical", ...)
 
-\method{degrees_of_freedom}{default}(model, method = "analytical", ...)
-
-dof(model, ...)
+dof(model, method = "analytical", ...)
 }
 \arguments{
 \item{model}{A statistical model.}
 
-\item{...}{Currently not used.}
-
 \item{method}{Can be \code{"analytical"} (default, DoFs are estimated based
 on the model type), \code{"residual"} in which case they are directly taken
 from the model if available (for Bayesian models, the goal (looking for
@@ -25,6 +20,8 @@ before extracting the DoFs), \code{"ml1"} (see \code{\link[=dof_ml1]{dof_ml1()}}
 (see \code{\link[=dof_betwithin]{dof_betwithin()}}), \code{"satterthwaite"} (see \code{\link[=dof_satterthwaite]{dof_satterthwaite()}}),
 \code{"kenward"} (see \code{\link[=dof_kenward]{dof_kenward()}}) or \code{"any"}, which tries to extract DoF
 by any of those methods, whichever succeeds. See 'Details'.}
+
+\item{...}{Currently not used.}
 }
 \description{
 Estimate or extract degrees of freedom of models parameters.
@@ -65,16 +62,15 @@ Furthermore, for other approximation methods like \code{"kenward"} or
 freedom.
 }
 \examples{
+\dontshow{if (require("lme4", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
 model <- lm(Sepal.Length ~ Petal.Length * Species, data = iris)
 dof(model)
 
 model <- glm(vs ~ mpg * cyl, data = mtcars, family = "binomial")
 dof(model)
 \donttest{
-if (require("lme4", quietly = TRUE)) {
-  model <- lmer(Sepal.Length ~ Petal.Length + (1 | Species), data = iris)
-  dof(model)
-}
+model <- lmer(Sepal.Length ~ Petal.Length + (1 | Species), data = iris)
+dof(model)
 
 if (require("rstanarm", quietly = TRUE)) {
   model <- stan_glm(
@@ -86,4 +82,5 @@ if (require("rstanarm", quietly = TRUE)) {
   dof(model)
 }
 }
+\dontshow{\}) # examplesIf}
 }