There exist many access control models in the literature, and several models are emerging each year. Yet, there is no formal taxonomy to compare the administrative features of these models. We propose a novel formalism to compare access control administration models based on their expressivity in a) administrative decentralization and b) conflict resolution. The contribution is a taxonomy by which one can categorize a given access control administration model in the space of all models within two axes: axis of decentralization degree of administration and axis of interpretation level of conflict resolution. In particular, five degrees of decentralization and four levels of interpretation are developed, as guidelines. Finally, six well-known administration models, including the widely used System R, are compared by using this technique. We conclude how the comparison can intuitively comment on each model in the context of their administrative functionality, performance, and security.