identity assurance

Definition

The heavy-lifting to be done by a trusted (middle-man) party to establish - and then offer reputational trust. An example of such a party is GLEIF. Instead, KERI is for attributional trust. In the real world you need both.
Read more in source Universal Identifier Theory

Out-of-band

A trusted party might use out-of-band procedures to assure the identity of people (representing parties) but it's not the same as Out-of-band Introductions (OOBIs) to establish attributional trust, which is done with KERI.