| GLECI {assocInd} | R Documentation |
The Group Location Error Corrected Index
Description
Calculates the Group Location Error Corrected Index
Usage
GLECI(x, Ya, Yb, Yab, Ynull, w)
Arguments
x |
Number of times individuals a and b were observed together |
Ya |
Number of times individual a was observed without b |
Yb |
Number of times individual b was observed without a |
Yab |
Number of times individuals a and b were observed at the same time but not associating |
Ynull |
Number of times neither a or b were observed |
w |
The correction term w (see details) |
Details
The GLECI calculates the probability that two individuals are observed together given that one has been seen, correcting for group location error (missing entire groups during a sampling period). This index can be used if prior information is available on the observation probability of finding groups, where the correction factor w is based on calibration data suggesting that failing to observe a group containing both a and b when they are together is w times more (w > 0) or less (w < 0) likely than failing to observe both the group containing a and the group containing b when a and b are apart.
Value
Returns two elements: the estimated association strength and the standard error of the estimate.
Author(s)
William Hoppitt <W.J.E.Hoppitt@leeds.ac.uk> Damien Farine <dfarine@orn.mpg.de>
References
Hoppitt, W. & Farine, D.R. (in prep) Association indices for quantifying social relationships: how to deal with missing observations of individuals or groups.
Examples
# Simulated values
x <- ya <- yb <- yab <- 10
ynull <- 0
# Set w (here make the GLECI equal to the SRI)
w <- 1.0
# Calculate the group location error corrected index
GLECI(x,ya,yb,yab,ynull,w)