During the development and validation of industrial hygiene monitoring methods in the laboratory, various parameters of collection, storage, and analysis are studied. It is not feasible, however, to study all the environmental variables in the laboratory, so field validation is necessary to detect problems which are specific to the actual work site. A statistical procedure to evaluate the field validation experiment is described together with the methodology necessary to perform these experiments and the equipment to facilitate these experiments. These procedures are demonstrated in an experiment measuring acrylonitrile in the workplace.