We have developed an attribute taxonomy that provides a useful categorization of issues about attributes, and notably their values, in regard to their impacts on consent and attribute release. See https://docs.google.com/document/d/13cFEpkaerCgit-aPPek2VZBFLwp7XhixZz0MHuZkdx8/edit?usp=sharing
A Rough Consensus is emerging on the characteristics for a consent mechanism to satisfy a diverse set of legal requirements, be effective for end-users, and foster a Internet-scale infrastructure to support it. These items are consumed by the IdP operator and/or by the end-user.
...