Autonomy is an often cited but rarely agreed upon agent characteristic. Alt
hough no definition of agent autonomy is universally accepted, the concept
of adaptive autonomy promises increasingly flexible and robust agent-based
systems. In general, adaptive autonomy gives agents the ability to seek hel
p for problems or take initiative when otherwise they would be constrained
by their design to follow some fixed procedures or rules for interacting wi
th other agents. In order to access these benefits, this article provides a
core definition and representation of agent autonomy designed to support t
he implementation of adaptive agent autonomy. This definition identifies "d
ecision-making control" governing the determination of agent goals and task
s as the key dimension of agent autonomy. In order to gain run-time flexibi
lity and any associated performance improvements, agents must be able to dy
namically adapt their autonomy during system operation. This article justif
ies the implementation of dynamic adaptive autonomy through a series of exp
eriments showing that a multiagent system operating under dynamic adaptive
autonomy performs better than a multiagent system operating under fixed aut
onomy for the same changing run-time conditions.