The field of foreign policy analysis needs a common set of concepts and analytical frameworks to facilitate comparison of alternative policy options. Not only is general agreement lacking, there is not even a common understanding of what is meant by success. In order to build policy-relevant knowledge concerning success and failure in foreign policy, the following questions must be addressed: How effective is a policy instrument likely to be, with respect to which goals and targets, at what cost, and in comparison with what other policy instruments? Failure to address each question may lead to serious policy mistakes.