R/i_esize_T.R

In tmnaylor/r4lineups: Statistical Inference on Lineup Fairness

#'I Component of Effective Size(Tredoux, 1998)
#'
#'Function for generating I component of effective size
#'@param lineup_table A table of lineup choices
#'@references Malpass, R. S. (1981). Effective size and defendant bias in
#'            eyewitness identification lineups. \emph{Law and Human Behavior, 5}(4), 299-309.
#'
#'            Malpass, R. S., Tredoux, C., & McQuiston-Surrett, D. (2007). Lineup
#'            construction and lineup fairness. In R. Lindsay, D. F. Ross, J. D. Read,
#'            & M. P. Toglia (Eds.), \emph{Handbook of Eyewitness Psychology, Vol. 2: Memory for
#'            people} (pp. 155-178). Mahwah, NJ: Lawrence Erlbaum Associates.
#'
#'            Tredoux, C. G. (1998). Statistical inference on measures of lineup fairness.
#'            \emph{Law and Human Behavior, 22}(2), 217-237.
#'
#'            Tredoux, C. (1999). Statistical considerations when determining measures of
#'            lineup size and lineup bias. \emph{Applied Cognitive Psychology}, 13, S9-S26.
#'
#'            Wells, G. L.,Leippe, M. R., & Ostrom, T. M. (1979). Guidelines for
#'            empirically assessing the fairness of a lineup. \emph{Law and Human Behavior,
#'            3}(4), 285-293.
#'@examples
#'#Data:
#'lineup_vec <- round(runif(100, 1, 6))
#'lineup_table <- table(lineup_vec)
#'
#'#Call:
#'i <- i_esize_T(lineup_table)
#'
#'@export
#'

i_esize_T <- function(lineup_table){
  i <- 1-(1/(sum(lineup_table)^2))*sum(lineup_table^2)
}