probability of winning or losing subsequent contests
(Jackson 1991; Hsu & Wolf 1999). To assess the relation
between individual-specific traits and ability, we assumed
the abilities to be related to measured traits x1,.,xp
through a linear predictor with coefficients b1,.,bp in
the familiar form:
li ¼X
p
r¼1
brxir :
The model used is thus a structured (through the assumption
of a linear predictor of ability) and generalized
(through the addition of the contest-specific experience
variable) version of the standard B–T model.