The principal–agent problem (also known as agency dilemma or theory of agency) occurs when one person or entity (the "agent") is able to make decisions on behalf of, or that impact, another person or entity: the "principal". The dilemma exists because sometimes the agent is motivated to act in his own best interests rather than those of the principal. The agent-principal relationship is a useful analytic tool in political science and economics, but may also apply to other areas.