We are more used to the term "Federated Identity" when dealing with IDM. But James McGovern asked a question wondering about a occasional dependence between these two.
Pat Patterson has given a decent outlook on this linking SAML and XACML.
Now, Conor has wildly dismissed the need for Federated Authorization when dealing with Federated Identity. I totally agree with Conor.
Federated Identity and Federated Authorization
I guess, James realized that his question did not get across properly, which I think is genuine.