An external evaluation is conducted by an evaluator who is not an employee of the organization that houses the object of the evaluation (e.g., the program). An external evaluator brings objectivity, accountability, and perspective to the problem at hand.

A key characteristic that distinguishes an external evaluation from an internal one is the objectivity of the evaluator. An external evaluation is governed by the terms of a contract between the organization and the evaluation consultant that are specific to the tasks of the evaluation project and are limited in duration to the life of the project. Contractual obligations tend to hold the evaluator's focus on the parameters of the evaluation itself and seldom allow the consultant to get involved in broader organizational issues. The bonds are ...