MELIBEA provides a searchable directory of open access (OA) policies. It describes the existing policies of each mandate listed and provides a clear list of criteria (e.g. length of possible embargo).
It also describes itself as a validator as it assesses each policy against a fixed set of qualitative and quantitative criteria. These are used to provide each mandate with a score that indicates how 'open' it is. For example the Wellcome mandate scores c.72% open, whereas the European Research Council (ERC) scores 60% openness.