Many multiagent systems are environments where distinct decision-makers compete, explicitly or implicitly, for scarce resources. In these competitive environments, itcan be advantageous for agents to cooperate and form teams, or coalitions; this cooperation gives agents strategic advantage to compete for scarce resources. Multiagent systems thus can be characterized in terms of competition and cooperation. To evaluate the effectiveness of cooperation for particular coalitions, we derive measures based on comparing these different coalitions at their respective equilibria. However, relying on equilibrium results leads to the interesting question of stability. Control theory and cooperative game theory have limitations that make it hard to apply them to study our questions about stabililty and evaluate cooperation in competitive environments. In this thesis we will lay a foundation towards a theory of coalition stability and robustness for multiagent systems. We then apply this condition to form a methodology toevaluate cooperation for market structure analysis.