Several organizations have given considerable attention to the development of criteria by which a laboratory may be evaluated. These range from generic to specific for laboratories engaged in a defined class of measurements. The evaluation may be performed by an individual requiring an individual service, or it may be required by some organization or agency as a basis for acceptance of services and/or data. There are basically two systems of accreditation of laboratories. One may be called "product focus" and the other "discipline focus." The former accredits or certifies capability to do rather specific measurements while the latter is more general. Self-evaluation is a hallmark of a well-managed laboratory. It has been said that a skeptical analytical chemist is the only one worthy of the name. Accordingly, each laboratory should have a systematic plan for critical review and appraisal of its program and outputs.