in an effort to take stock of existing initiatives the oecd inventory water governance indicators and measurement frameworks launched on line in october mapped instruments eg indicators maps databases and assessment tools see table for measuring and evaluating several water governance aspects most of these indicators relate to specific functions water sanitation and hygiene and integrated water resources management scales eg national basin or governance dimensions transparency capacity etc the most relevant toolkits and indicators for the implementation of the oecd principles on water governance are summarised in table the challenges are related to the complexity of the water governance dimensions to be assessed data availability data collection through expert views comparability over space and time and the difficulty in drawing causality linkages between outcomes measured by indicators and policies aiming at generating certain impacts figure it contains evidencebased tools and advice as well as country examples showcasing practices which have been successfully tested in a number of countries