External evaluators are somewhat isolated, often lacking knowledge of and experience with the program. Evaluation of this nature is also more expensive, since an additional person must be hired to carry out the work. However, an external evaluator: (1) can often provide a more objective review and a fresh perspective, (2) can help to ensure an unbiased evaluation outcome, (3) brings a global knowledge of evaluation having worked in a variety of settings, and (4) "typically brings more breadth and depth of technical expertise" Sometimes, external evaluators may not charge for evaluation services if they are given permission to publish program results in scientific or academic settings (e.g., peer-viewed journals and conferences). With this type of arrangement, stakeholders relinquish full ownership of data and program results. When selecting an external evaluator, planners should look for someone with formal training in evaluation methods and related experience