R/discount.R

In healthiar: Quantifying and Monetizing Health Impacts Attributable to Exposure

#' Discount health impacts

# DESCRIPTION ##################################################################
#' @description
#' This function calculates discounted health impacts (without valuation).

# ARGUMENTS ####################################################################
#' @inheritParams monetize
#'
#'
#'
# DETAILS ######################################################################
#' @details
#'
#' \strong{Methodology}
#'
#' This function applies a discount to attributable health impacts into the future.
#'
#' One of the following three discount shapes can be selected:
#' \itemize{
#'  \item Exponential \insertCite{Frederick2002_jel}{healthiar}
#'  \item Hyperbolic as \insertCite{Harvey1986_ms;textual}{healthiar}
#'  \item Hyperbolic as \insertCite{Mazur1987_book;textual}{healthiar}}
#'
#' Burden of disease studies may be interested in calculating +
#' discounted health impacts over time,
#' and these may also be used in economic evaluation models,
#' where benefits are not monetized.
#' For this specific purpose, this function is offered.
#'
#'
#' Detailed information about the methodology (including equations)
#' is available in the package vignette.
#' More specifically, see chapters:
#' \itemize{
#'  \item \href{https://swisstph.github.io/healthiar/articles/intro_to_healthiar.html#monetization}{Monetization}}
#'
#'
# VALUE ########################################################################
#' @inherit monetize return

# EXAMPLES #####################################################################
#' @examples
#' # Goal: discount attributable health impacts
#' results <- discount(
#'   impact = 20000,
#'   discount_shape = "exponential",
#'   discount_rate = 0.03,
#'   n_years = 20
#' )
#' results$monetization_main$monetized_impact
#'
#'
#' @seealso
#' \itemize{
#'   \item Upstream: \code{\link{attribute_health}}, \code{\link{attribute_health}}
#'   \item Alternative: \code{\link{monetize}}
#' }
#'
# REFERENCES #####################################################################
#' @references
#'
#' \insertAllCited{}
#'
#'
#' @author Alberto Castro & Axel Luyten
#'
#' @export



discount <-
  function(output_attribute = NULL,
           impact = NULL,
           discount_rate = NULL,
           n_years = NULL,
           discount_shape = NULL) {

    output_discounting <-
      monetize(
        output_attribute = output_attribute,
        impact = impact,
        discount_rate = discount_rate,
        n_years = n_years,
        discount_shape = discount_shape,
        valuation = 1)


    output_discounting[["monetization_main"]] <-
      output_discounting[["monetization_main"]] |>
      dplyr::select(-dplyr::contains("cost"))


    return(output_discounting)


  }