As ecosystem assessments represent syntheses of knowledge on ecosystem status created to answer key policy questions, it is important to identify whether the dialogue between assessment practitioners and policy makers is delivering the goals which ecosystem assessment practitioners seek. A number of global and national ecosystem assessment processes are underway between now and 2020, and best practice in creating assessments which have stakeholder buy in and policy relevance is subject to continuing refinement. While there are few unequivocal examples of assessments driving policy change (due to political decision-making processes being affected by a multiplicity of considerations beyond the availability of evidence), building a strong case around which assessments have informed policy development will enhance future legitimacy of ecosystem assessments in political dialogue.