R/HSUV.R

In n8thangreen/QALY: Calculate Quality Adjusted Life Years (QALYs) Gains with Discounting and Inflated Costs

#' Health State Utility Value
#'
#' Utilities can be combined in different ways to give an overall utility.
#'
#'
#' TODO: Adjusted decrement estimator
#' TODO: Combination model
#'
#' @param method Options are:
#' \itemize{
#'  \item Additive
#' \deqn{u^{add} = u_a + u_b - 1}
#'  \item Multiplicative
#' \deqn{u^{mult} = u_a u_b}
#'  \item Minimum
#' \deqn{u^{min} = \min{u_a, u_b}}
#' }
#'
#' @param ... One or more utilities to combine
#'
#' @references \url{http://nicedsu.org.uk/wp-content/uploads/2016/03/TSD12-Utilities-in-modelling-FINAL.pdf}
#'
#' @return function
#' @export
#'
#' @examples
#'
#' HSUV(1,1)
#' HSUV(1,1,2)
#'
HSUV <- function(..., method = c("prod", "add", "min")) {

  if ("add" %in% method) method <-
      function(...) max(0, sum(...) - length(list(...)) + 1)

  function(...) {

    do.call(what = method, args = list(...))
  }
}