R/dci.R

In compete: Analyzing Social Hierarchies

#' Get the directional consistency index (DCI) of a sociomatrix.
#'
#' @param m A matrix with individuals ordered identically in rows and columns.
#' @return The directional consistency of \code{m}.
#' @examples
#' m <- matrix(c(NA,2,30,6,19,122,0,NA,18,
#' 0,19,85,0,1,NA,3,8,84,0,0,0,NA,267,50,0,
#' 0,0,5,NA,10,1,0,4,4,1,NA), ncol=6) #table 2, Vervaecke et al. 2000  - fleeing in bonobos
#' dci(m)
#' @section References:
#' Van Hooff JARAM, Wensing JAB. 1987.
#' Dominance and its behavioural measures in a captive wolf pack.
#' In: Frank HW, editor. Man and Wolf.
#' Dordrecht, Olanda (Netherlands): Junk Publishers
#' pp.219-252.
#' @section Further details:
#' The DCI represents the proportion of occurrences of a behavior
#' that occurs across all dyads in a group from the individual
#' within each dyad performing the behavior with a higher frequency (H)
#' to the individual within each dyad performing the behavior with
#' a lower frequency (L). It is calculated by averaging the following
#' formula across all dyads: DCI = (H - L)/(H + L). The DCI ranges from 0
#' (no directional asymmetry) to 1 (completely unidirectional).
#' @export

dci<-function(m){
  m<-as.matrix(m)
  diag(m)<-0
  N=sum(m)/2
  dc=sum(abs(m-t(m)))/2/sum(m)
 return(dc)
 }