The experimental aspects of the NIOSH Guidelines for Air Sampling and Analytical Method Development and Evaluation were summarized. A test of the ability to recover analyte from the sampling medium, by calculating the percent recovery of various concentrations of sample, was discussed. Reanalysis on the following day was advised. Time dependent sample stability, as well as analyte stability on the medium, were addressed. A means of testing sample stability consisted of storing known concentrations for 1 week under various conditions prior to analysis. The sample was considered stable if the percent recovery was not significantly affected by the duration or condition of the storage. When testing over a concentration range, the method provided a result within 25% of the true concentration 95% of the time, with an absolute bias of at most 10%. Several techniques involved collecting the sample from a generated atmosphere, with consideration of the appropriate environmental conditions. The authors suggest that the atmospheric particle concentration should be checked by analysis of replicate samples by an independent method. The capacity of the sampler should be determined as a function of flow rate and sampling time. The use of factorial design to test the effects of environmental conditions on the efficiency of the sampling medium was explored. Methods of field evaluation, which included personal and area samples, were also discussed. Documentation of the research was recommended as the final step. The authors conclude that standardized procedures for sampling and analytical methods are crucial to universally regarded research.