Tribal knowledge is knowledge that is known within an in-group of people but unknown outside of it. A tribe, in this sense, is a group of people that share such a common knowledge. In the context of corporations, tribal knowledge or know-how has been described most broadly as the collective wisdom of the organization and the sum of all the knowledge and capabilities of all the people;[1] however, in management science, it is usually viewed as a particular subset thereof: a type of institutional memory that lacks adequate documentation, such that its preservation in the organization over time relies solely on processes such as mentoring, apprenticeship, on-the-job training, and, at the heart of all of those, continuity of staffing, which is inherently vulnerable to employee turnover (of both workers and managers). It is knowledge that is necessary to an organization's function and yet is inadequately documented or otherwise captured.