The Procedure for Institutional Compatibility Assessment (PICA) has been developed as a formalised methodology to predict the compatibility between a policy option and the institutional context of its implementation. As a first empirical test of the tool, PICA was applied to the implementation of the EU Nitrate Directive in Auvergne, France. Valuable insights were acquired on the combination of experts and stakeholders' perspectives and the choice of qualitative methods for the collection of the information needed at each step of the assessment. Further, this procedure proved to be a valuable tool for the ex-ante identification of institutional factors affecting the implementation of policies.