diff --git a/NAMESPACE b/NAMESPACE
index baee88c7..3c868064 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -5,10 +5,14 @@ S3method("[",forecast)
 S3method("[<-",forecast)
 S3method("[[<-",forecast)
 S3method(`[`,scores)
+S3method(as_forecast_binary,default)
+S3method(as_forecast_nominal,default)
+S3method(as_forecast_ordinal,default)
 S3method(as_forecast_point,default)
 S3method(as_forecast_point,forecast_quantile)
 S3method(as_forecast_quantile,default)
 S3method(as_forecast_quantile,forecast_sample)
+S3method(as_forecast_sample,default)
 S3method(assert_forecast,default)
 S3method(assert_forecast,forecast_binary)
 S3method(assert_forecast,forecast_nominal)
@@ -40,7 +44,6 @@ export(add_relative_skill)
 export(ae_median_quantile)
 export(ae_median_sample)
 export(as_forecast_binary)
-export(as_forecast_nominal)
 export(as_forecast_ordinal)
 export(as_forecast_point)
 export(as_forecast_quantile)
diff --git a/R/class-forecast-binary.R b/R/class-forecast-binary.R
index 09fc1704..0c36ee85 100644
--- a/R/class-forecast-binary.R
+++ b/R/class-forecast-binary.R
@@ -18,11 +18,11 @@
 #'
 #' See the [example_binary] data set for an example.
 #' @inheritSection forecast_types Forecast unit
+#' @param ... Unused
 #' @returns A `forecast` object of class `forecast_binary`
 #' @family functions to create forecast objects
-#' @importFrom cli cli_warn
-#' @keywords as_forecast
 #' @export
+#' @keywords as_forecast transform
 #' @examples
 #' as_forecast_binary(
 #'   example_binary,
@@ -30,10 +30,19 @@
 #'   forecast_unit = c("model", "target_type", "target_end_date",
 #'                     "horizon", "location")
 #' )
-as_forecast_binary <- function(data,
-                               forecast_unit = NULL,
-                               observed = NULL,
-                               predicted = NULL) {
+as_forecast_binary <- function(data, ...) {
+  UseMethod("as_forecast_binary")
+}
+
+#' @rdname as_forecast_binary
+#' @export
+#' @method as_forecast_binary default
+#' @importFrom cli cli_warn
+as_forecast_binary.default <- function(data,
+                                       forecast_unit = NULL,
+                                       observed = NULL,
+                                       predicted = NULL,
+                                       ...) {
   data <- as_forecast_generic(
     data,
     forecast_unit,
@@ -45,7 +54,6 @@ as_forecast_binary <- function(data,
   return(data)
 }
 
-
 #' @export
 #' @rdname assert_forecast
 #' @importFrom cli cli_abort
diff --git a/R/class-forecast-nominal.R b/R/class-forecast-nominal.R
index c589b585..8c076dc5 100644
--- a/R/class-forecast-nominal.R
+++ b/R/class-forecast-nominal.R
@@ -7,7 +7,8 @@
 #'
 #' # Required input
 #'
-#' The input needs to be a data.frame or similar with the following columns:
+#' The input needs to be a data.frame or similar for the default method
+#' with the following columns:
 #' - `observed`: Column with observed values of type `factor` with N levels,
 #'    where N is the number of possible outcomes.
 #'    The levels of the factor represent the possible outcomes that
@@ -26,13 +27,11 @@
 #'
 #' See the [example_nominal] data set for an example.
 #' @inheritSection forecast_types Forecast unit
-#' @param predicted_label (optional) Name of the column in `data` that denotes
-#'   the outcome to which a predicted probability corresponds to.
-#'   This column will be renamed to "predicted_label".
+#' @param ... Unused
 #' @returns A `forecast` object of class `forecast_nominal`
 #' @family functions to create forecast objects
-#' @keywords as_forecast
-#' @export
+#' @keywords as_forecast transform
+#' @export4
 #' @examples
 #' as_forecast_nominal(
 #'   na.omit(example_nominal),
@@ -40,11 +39,23 @@
 #'   forecast_unit = c("model", "target_type", "target_end_date",
 #'                     "horizon", "location")
 #' )
-as_forecast_nominal <- function(data,
-                                forecast_unit = NULL,
-                                observed = NULL,
-                                predicted = NULL,
-                                predicted_label = NULL) {
+as_forecast_nominal <- function(data, ...) {
+  UseMethod("as_forecast_nominal")
+}
+
+#' @rdname as_forecast_nominal
+#' @param predicted_label (optional) Name of the column in `data` that denotes
+#'   the outcome to which a predicted probability corresponds to.
+#'   This column will be renamed to "predicted_label".
+#' @export
+#' @method as_forecast_nominal default
+#' @importFrom cli cli_warn
+as_forecast_nominal.default <- function(data,
+                                        forecast_unit = NULL,
+                                        observed = NULL,
+                                        predicted = NULL,
+                                        predicted_label = NULL,
+                                        ...) {
   data <- as_forecast_generic(
     data,
     forecast_unit,
diff --git a/R/class-forecast-ordinal.R b/R/class-forecast-ordinal.R
index d6dda020..d3bb4d9f 100644
--- a/R/class-forecast-ordinal.R
+++ b/R/class-forecast-ordinal.R
@@ -7,7 +7,8 @@
 #'
 #' # Required input
 #'
-#' The input needs to be a data.frame or similar with the following columns:
+#' The input needs to be a data.frame or similar for the default method
+#' with the following columns:
 #' - `observed`: Column with observed values of type `factor` with N ordered
 #'   levels, where N is the number of possible outcomes.
 #'   The levels of the factor represent the possible outcomes that
@@ -26,13 +27,11 @@
 #'
 #' See the [example_ordinal] data set for an example.
 #' @inheritSection forecast_types Forecast unit
-#' @param predicted_label (optional) Name of the column in `data` that denotes
-#'   the outcome to which a predicted probability corresponds to.
-#'   This column will be renamed to "predicted_label".
-#' @returns A `forecast` object of class `forecast_ordinal`
+#' @param ... Unused
 #' @family functions to create forecast objects
-#' @keywords as_forecast
+#' @returns A `forecast` object of class `forecast_ordinal`
 #' @export
+#' @keywords as_forecast transform
 #' @examples
 #' as_forecast_ordinal(
 #'   na.omit(example_ordinal),
@@ -40,11 +39,23 @@
 #'   forecast_unit = c("model", "target_type", "target_end_date",
 #'                     "horizon", "location")
 #' )
-as_forecast_ordinal <- function(data,
-                                forecast_unit = NULL,
-                                observed = NULL,
-                                predicted = NULL,
-                                predicted_label = NULL) {
+as_forecast_ordinal <- function(data, ...) {
+  UseMethod("as_forecast_ordinal")
+}
+
+#' @rdname as_forecast_ordinal
+#' @param predicted_label (optional) Name of the column in `data` that denotes
+#'   the outcome to which a predicted probability corresponds to.
+#'   This column will be renamed to "predicted_label".
+#' @export
+#' @method as_forecast_ordinal default
+#' @importFrom cli cli_warn
+as_forecast_ordinal.default <- function(data,
+                                        forecast_unit = NULL,
+                                        observed = NULL,
+                                        predicted = NULL,
+                                        predicted_label = NULL,
+                                        ...) {
   data <- as_forecast_generic(
     data,
     forecast_unit,
diff --git a/R/class-forecast-point.R b/R/class-forecast-point.R
index 7e2aa9eb..2cda639c 100644
--- a/R/class-forecast-point.R
+++ b/R/class-forecast-point.R
@@ -3,7 +3,8 @@
 #' @details
 #' # Required input
 #'
-#' The input needs to be a data.frame or similar with the following columns:
+#' The input needs to be a data.frame or similar for the default method
+#' with the following columns:
 #' - `observed`: Column of type `numeric` with observed values.
 #' - `predicted`: Column of type `numeric` with predicted values.
 #'
@@ -24,6 +25,7 @@ as_forecast_point <- function(data, ...) {
 
 #' @rdname as_forecast_point
 #' @export
+#' @method as_forecast_point default
 #' @importFrom cli cli_warn
 as_forecast_point.default <- function(data,
                                       forecast_unit = NULL,
diff --git a/R/class-forecast-quantile.R b/R/class-forecast-quantile.R
index ac341ee2..169b52a1 100644
--- a/R/class-forecast-quantile.R
+++ b/R/class-forecast-quantile.R
@@ -3,7 +3,8 @@
 #' @details
 #' # Required input
 #'
-#' The input needs to be a data.frame or similar with the following columns:
+#' The input needs to be a data.frame or similar for the default method
+#' with the following columns:
 #' - `observed`: Column of type `numeric` with observed values.
 #' - `predicted`: Column of type `numeric` with predicted values. Predicted
 #'    values represent quantiles of the predictive distribution.
@@ -39,6 +40,7 @@ as_forecast_quantile <- function(data, ...) {
 #'   the quantile level of the predicted values. This column will be renamed to
 #'   "quantile_level". Only applicable to quantile-based forecasts.
 #' @export
+#' @method as_forecast_quantile default
 #' @importFrom cli cli_warn
 as_forecast_quantile.default <- function(data,
                                          forecast_unit = NULL,
diff --git a/R/class-forecast-sample.R b/R/class-forecast-sample.R
index 8252ca4d..a427a979 100644
--- a/R/class-forecast-sample.R
+++ b/R/class-forecast-sample.R
@@ -3,7 +3,8 @@
 #' @details
 #' # Required input
 #'
-#' The input needs to be a data.frame or similar with the following columns:
+#' The input needs to be a data.frame or similar for the default method
+#' with the following columns:
 #' - `observed`: Column of type `numeric` with observed values.
 #' - `predicted`: Column of type `numeric` with predicted values. Predicted
 #'    values represent random samples from the predictive distribution.
@@ -17,18 +18,27 @@
 #' See the [example_sample_continuous] and [example_sample_discrete] data set
 #' for an example
 #' @inheritSection forecast_types Forecast unit
+#' @param ... Unused
+#' @family functions to create forecast objects
+#' @returns A `forecast` object of class `forecast_sample`
+#' @export
+#' @keywords as_forecast transform
+as_forecast_sample <- function(data, ...) {
+  UseMethod("as_forecast_sample")
+}
+
+
+#' @rdname as_forecast_sample
 #' @param sample_id (optional) Name of the column in `data` that contains the
 #'   sample id. This column will be renamed to "sample_id".
 #' @export
-#' @returns A `forecast` object of class `forecast_sample`
-#' @family functions to create forecast objects
 #' @importFrom cli cli_warn
-#' @keywords as_forecast
-as_forecast_sample <- function(data,
-                               forecast_unit = NULL,
-                               observed = NULL,
-                               predicted = NULL,
-                               sample_id = NULL) {
+as_forecast_sample.default <- function(data,
+                                       forecast_unit = NULL,
+                                       observed = NULL,
+                                       predicted = NULL,
+                                       sample_id = NULL,
+                                       ...) {
   data <- as_forecast_generic(
     data,
     forecast_unit,
diff --git a/man/as_forecast_binary.Rd b/man/as_forecast_binary.Rd
index 73dd4213..ac33fc81 100644
--- a/man/as_forecast_binary.Rd
+++ b/man/as_forecast_binary.Rd
@@ -2,13 +2,17 @@
 % Please edit documentation in R/class-forecast-binary.R
 \name{as_forecast_binary}
 \alias{as_forecast_binary}
+\alias{as_forecast_binary.default}
 \title{Create a \code{forecast} object for binary forecasts}
 \usage{
-as_forecast_binary(
+as_forecast_binary(data, ...)
+
+\method{as_forecast_binary}{default}(
   data,
   forecast_unit = NULL,
   observed = NULL,
-  predicted = NULL
+  predicted = NULL,
+  ...
 )
 }
 \arguments{
@@ -16,6 +20,8 @@ as_forecast_binary(
 See the details section of for additional information
 on the required input format.}
 
+\item{...}{Unused}
+
 \item{forecast_unit}{(optional) Name of the columns in \code{data} (after
 any renaming of columns) that denote the unit of a
 single forecast. See \code{\link[=get_forecast_unit]{get_forecast_unit()}} for details.
@@ -107,3 +113,4 @@ Other functions to create forecast objects:
 }
 \concept{functions to create forecast objects}
 \keyword{as_forecast}
+\keyword{transform}
diff --git a/man/as_forecast_nominal.Rd b/man/as_forecast_nominal.Rd
index a578a422..f332d5de 100644
--- a/man/as_forecast_nominal.Rd
+++ b/man/as_forecast_nominal.Rd
@@ -2,14 +2,18 @@
 % Please edit documentation in R/class-forecast-nominal.R
 \name{as_forecast_nominal}
 \alias{as_forecast_nominal}
+\alias{as_forecast_nominal.default}
 \title{Create a \code{forecast} object for nominal forecasts}
 \usage{
-as_forecast_nominal(
+as_forecast_nominal(data, ...)
+
+\method{as_forecast_nominal}{default}(
   data,
   forecast_unit = NULL,
   observed = NULL,
   predicted = NULL,
-  predicted_label = NULL
+  predicted_label = NULL,
+  ...
 )
 }
 \arguments{
@@ -17,6 +21,8 @@ as_forecast_nominal(
 See the details section of for additional information
 on the required input format.}
 
+\item{...}{Unused}
+
 \item{forecast_unit}{(optional) Name of the columns in \code{data} (after
 any renaming of columns) that denote the unit of a
 single forecast. See \code{\link[=get_forecast_unit]{get_forecast_unit()}} for details.
@@ -55,7 +61,8 @@ generalisation of binary forecasts to multiple outcomes. The possible
 outcomes that the observed values can assume are not ordered.
 }
 \section{Required input}{
-The input needs to be a data.frame or similar with the following columns:
+The input needs to be a data.frame or similar for the default method
+with the following columns:
 \itemize{
 \item \code{observed}: Column with observed values of type \code{factor} with N levels,
 where N is the number of possible outcomes.
@@ -121,3 +128,4 @@ Other functions to create forecast objects:
 }
 \concept{functions to create forecast objects}
 \keyword{as_forecast}
+\keyword{transform}
diff --git a/man/as_forecast_ordinal.Rd b/man/as_forecast_ordinal.Rd
index bfff8cff..2ba17ec1 100644
--- a/man/as_forecast_ordinal.Rd
+++ b/man/as_forecast_ordinal.Rd
@@ -2,14 +2,18 @@
 % Please edit documentation in R/class-forecast-ordinal.R
 \name{as_forecast_ordinal}
 \alias{as_forecast_ordinal}
+\alias{as_forecast_ordinal.default}
 \title{Create a \code{forecast} object for ordinal forecasts}
 \usage{
-as_forecast_ordinal(
+as_forecast_ordinal(data, ...)
+
+\method{as_forecast_ordinal}{default}(
   data,
   forecast_unit = NULL,
   observed = NULL,
   predicted = NULL,
-  predicted_label = NULL
+  predicted_label = NULL,
+  ...
 )
 }
 \arguments{
@@ -17,6 +21,8 @@ as_forecast_ordinal(
 See the details section of for additional information
 on the required input format.}
 
+\item{...}{Unused}
+
 \item{forecast_unit}{(optional) Name of the columns in \code{data} (after
 any renaming of columns) that denote the unit of a
 single forecast. See \code{\link[=get_forecast_unit]{get_forecast_unit()}} for details.
@@ -55,7 +61,8 @@ generalisation of binary forecasts to multiple outcomes. The possible
 outcomes that the observed values can assume are ordered.
 }
 \section{Required input}{
-The input needs to be a data.frame or similar with the following columns:
+The input needs to be a data.frame or similar for the default method
+with the following columns:
 \itemize{
 \item \code{observed}: Column with observed values of type \code{factor} with N ordered
 levels, where N is the number of possible outcomes.
@@ -121,3 +128,4 @@ Other functions to create forecast objects:
 }
 \concept{functions to create forecast objects}
 \keyword{as_forecast}
+\keyword{transform}
diff --git a/man/as_forecast_point.Rd b/man/as_forecast_point.Rd
index 7cf164b1..484c4695 100644
--- a/man/as_forecast_point.Rd
+++ b/man/as_forecast_point.Rd
@@ -47,7 +47,8 @@ When converting a \code{forecast_quantile} object into a \code{forecast_point} o
 the 0.5 quantile is extracted and returned as the point forecast.
 }
 \section{Required input}{
-The input needs to be a data.frame or similar with the following columns:
+The input needs to be a data.frame or similar for the default method
+with the following columns:
 \itemize{
 \item \code{observed}: Column of type \code{numeric} with observed values.
 \item \code{predicted}: Column of type \code{numeric} with predicted values.
diff --git a/man/as_forecast_quantile.Rd b/man/as_forecast_quantile.Rd
index cc971666..de012aec 100644
--- a/man/as_forecast_quantile.Rd
+++ b/man/as_forecast_quantile.Rd
@@ -72,7 +72,8 @@ the columns that uniquely identify a single forecast (and thereby removing
 other, unneeded columns. See section "Forecast Unit" below for details).
 }
 \section{Required input}{
-The input needs to be a data.frame or similar with the following columns:
+The input needs to be a data.frame or similar for the default method
+with the following columns:
 \itemize{
 \item \code{observed}: Column of type \code{numeric} with observed values.
 \item \code{predicted}: Column of type \code{numeric} with predicted values. Predicted
diff --git a/man/as_forecast_sample.Rd b/man/as_forecast_sample.Rd
index 3ea3d393..b3ebb237 100644
--- a/man/as_forecast_sample.Rd
+++ b/man/as_forecast_sample.Rd
@@ -2,14 +2,18 @@
 % Please edit documentation in R/class-forecast-sample.R
 \name{as_forecast_sample}
 \alias{as_forecast_sample}
+\alias{as_forecast_sample.default}
 \title{Create a \code{forecast} object for sample-based forecasts}
 \usage{
-as_forecast_sample(
+as_forecast_sample(data, ...)
+
+\method{as_forecast_sample}{default}(
   data,
   forecast_unit = NULL,
   observed = NULL,
   predicted = NULL,
-  sample_id = NULL
+  sample_id = NULL,
+  ...
 )
 }
 \arguments{
@@ -17,6 +21,8 @@ as_forecast_sample(
 See the details section of for additional information
 on the required input format.}
 
+\item{...}{Unused}
+
 \item{forecast_unit}{(optional) Name of the columns in \code{data} (after
 any renaming of columns) that denote the unit of a
 single forecast. See \code{\link[=get_forecast_unit]{get_forecast_unit()}} for details.
@@ -49,7 +55,8 @@ the columns that uniquely identify a single forecast (and thereby removing
 other, unneeded columns. See section "Forecast Unit" below for details).
 }
 \section{Required input}{
-The input needs to be a data.frame or similar with the following columns:
+The input needs to be a data.frame or similar for the default method
+with the following columns:
 \itemize{
 \item \code{observed}: Column of type \code{numeric} with observed values.
 \item \code{predicted}: Column of type \code{numeric} with predicted values. Predicted
@@ -102,3 +109,4 @@ Other functions to create forecast objects:
 }
 \concept{functions to create forecast objects}
 \keyword{as_forecast}
+\keyword{transform}