assocInd (version 1.0.1)

GLECI: 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)

Value

Returns two elements: the estimated association strength and the standard error of the estimate.

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.

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)