There are several different kinds of oral examinations used in practice. The "Disputation", also called "Verteidigung" ("defense"), is usually public (at least to members of the university) and is focused on the topic of the thesis. In contrast, the "Rigorosum" is not held in public and also encompasses fields in addition to the topic of the thesis. The "Rigorosum" is only common for doctoral degrees. Another term for an oral examination is "Kolloquium", which generally refers to a usually public scientific discussion and is often used synonymously with "Verteidigung".