In a number of countries, the title "research professor" refers to a professor who is exclusively or mainly engaged in research, and who has few or no teaching obligations. For example, the title is used in this sense in the United Kingdom (where it is known as research professor at some universities and professorial research fellow at some other institutions) and in northern Europe. Research professor is usually the most senior rank of a research-focused career pathway in those countries, and regarded as equal to the ordinary full professor rank. Most often they are permanent employees, and the position is often held by particularly distinguished scholars; thus the position is often seen as more prestigious than an ordinary full professorship. The title is used in a somewhat similar sense in the United States, with the exception that research professors in the United States are often not permanent employees and often must fund their salary from external sources, which is usually not the case elsewhere.