e.single {EloRating}

Elo ratings for a single interaction

Description

calculate/update Elo ratings for a single dyadic interaction

Usage

e.single(ELO1old, ELO2old, outcome, k = 100, normprob = TRUE)

Arguments

ELO1old, ELO2old

numeric, Elo rating of the first and second individual

outcome

1 = first individual wins and second looses
2 = second individual wins and first looses
0 = interaction ends in a draw/tie (no winner and no looser)

k

numeric, k factor, by default k = 100

normprob

logical (by default TRUE). Should a normal curve be assumed for calculating the winning/losing probablities, or a logistic curve. See winprob for details

Value

integer vector of length 2 with updated ratings of first and second individual after the interaction

Author(s)

Christof Neumann

References

Elo AE (1978). The rating of chess players, past and present. Arco, New York.

Albers PCH, de Vries H (2001). “Elo-rating as a tool in the sequential estimation of dominance strengths.” Animal Behaviour, 61, 489-495. doi:10.1006/anbe.2000.1571.

Examples

e.single(ELO1old = 1200, ELO2old = 1000, outcome = 1, k = 100)
# same as before
e.single(ELO1old = 1000, ELO2old = 1200, outcome = 2, k = 100)
# an undecided interaction
e.single(ELO1old = 1200, ELO2old = 1000, outcome = 0, k = 100)
# if rating differences are too big, no change occurs
# if higher-rated individual wins
e.single(ELO1old = 2000, ELO2old = 1000, outcome = 1, k = 100)
# same as before but lower-rated individual wins and
# therefore wins maximum number of points possible (i.e. k)
e.single(ELO1old = 2000, ELO2old = 1000, outcome = 2, k = 100)