R/tau2h-vc.r

In nshi-stat/pimeta: Prediction Intervals for Random-Effects Meta-Analysis

# Variance component type estimator for \eqn{\tau^2}
# 
# Returns the variance component type estimator
# for \eqn{\tau^2} (Hedges, 1983).
# 
# @name tau2h_vc
# @rdname tau2h_vc
# @param y the effect size estimates vector
# @param se the within studies standard errors vector
# @return
# \itemize{
# \item \code{tau2h}: the estimate for \eqn{\tau^2}.
# }
# @references
# Hedges, L. V. (1983).
# A random effects model for effect sizes.
# \emph{Psychol Bull.}
# \strong{93}(2): 388-395. 
# @export
tau2h_vc <- function(y, se) {
  
  k <- length(y)
  tau2h <- max(0.0, sum(y - sum(y)/k)^2/(k - 1.0) - sum(se)/k)
  
  return(list(tau2h = tau2h))
  
}