R/mice.impute.mean.R

In mice: Multivariate Imputation by Chained Equations

#' Imputation by the mean
#'
#' Imputes the arithmetic mean of the observed data
#'
#' @inheritParams mice.impute.pmm
#' @return Vector with imputed data, same type as \code{y}, and of length
#' \code{sum(wy)}
#' @section Warning: Imputing the mean of a variable is almost never
#' appropriate.  See Little and Rubin (2002, p. 61-62) or
#' Van Buuren (2012, p. 10-11)
#' @seealso \code{\link{mice}}, \code{\link{mean}}
#' @references Van Buuren, S., Groothuis-Oudshoorn, K. (2011). \code{mice}:
#' Multivariate Imputation by Chained Equations in \code{R}. \emph{Journal of
#' Statistical Software}, \bold{45}(3), 1-67.
#' \doi{10.18637/jss.v045.i03}
#'
#' Little, R.J.A. and Rubin, D.B. (2002). Statistical Analysis with Missing
#' Data.  New York: John Wiley and Sons.
#'
#' Van Buuren, S. (2018).
#' \href{https://stefvanbuuren.name/fimd/sec-simplesolutions.html#sec:meanimp}{\emph{Flexible Imputation of Missing Data. Second Edition.}}
#' Chapman & Hall/CRC. Boca Raton, FL.
#' @family univariate imputation functions
#' @keywords datagen
#' @export
mice.impute.mean <- function(y, ry, x = NULL, wy = NULL, ...) {
  if (is.null(wy)) {
    wy <- !ry
  }
  rep.int(mean(y[ry]), times = sum(wy))
}