—also known as "multi-rater feedback," "multisource feedback," and "multisource assessment"—refers to compiled evaluations provided by those who work “all around” an employee. The program gets its name from a 360-degree circle, implying that the individual being evaluated is in the center of a circle of his or her peers, supervisors, and subordinates. In addition to feedback from fellow employees, it also includes a self-assessment and, in some cases, feedback from customers, suppliers, and other external sources. In many organizations, 360 feedback is included as a supplement to traditional performance reviews, where managers evaluate the work of their direct reports.
Source: http://en.wikipedia.org/wiki/360-degree_feedback

In most cases, 360 feedback is not recommended as a replacement for traditional managerial reviews, but as an additional development tool that allows employees to gauge their strengths, weaknesses, and behaviors. Employees receive anonymous feedback from their co-workers, providing valuable insights into what they can do to enhance their professional growth and skill development.

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