The prime concern of the conference interpreter is to establish communication between parties pertaining to two different linguistic and cultural realities generally a speaker and his/her audience. End-users may find themselves dependent on the interpreter to varying degrees: from total dependence when they lack knowledge of the source language (SL) to partial. In the many different situational contexts of multi-lingual conferences, an interpreter-user interaction will develop, determined by acoustic and visual factors, leading to a personal evaluation of the interpreter’s performance by individual members of the audience. This paper provides an overview of studies on Quality Assessment of simultaneous and consecutive interpretation.