In performing arts, generally comprises an event in which a performer or group of performers behave in a particular way for another group of people, the audience./ A performance indicator or key performance indicator (KPI) is a type of performance measurement. An organization may use KPIs to evaluate its success, or to evaluate the success of a particular activity in which it is engaged.
Sometimes success is defined in terms of making progress toward strategic goals, but often success is simply the repeated, periodic achievement of some level of operational goal (e.g. zero defects, 10/10 customer satisfaction, etc.). Accordingly, choosing the right KPIs relies upon a good understanding of what is important to the organization. ‘What is important’ often depends on the department measuring the performance – e.g. the KPIs useful to finance will be quite different than the KPIs assigned to sales.
Since there is a need to well understand what is important (to an organization), various techniques to assess the present state of the business, and its key activities, are associated with the selection of performance indicators. These assessments often lead to the identification of potential improvements, so performance indicators are routinely associated with ‘performance improvement’ initiatives. A very common way to choose KPIs is to apply a management framework such as the balanced scorecard.

Source: http://en.wikipedia.org/wiki/Performance_indicator / http://en.wikipedia.org/wiki/Performance