Contracting-out is currently a popular method of getting analysis done. It is regarded as conferring two benefits: high quality, because you can select a firm that specialises in the type of analysis required; and low cost because the firm will be permanently set up for that kind of analysis and able to make savings of quantity. But how can you tell if the results you receive are of the quality required, that is, if the uncertainty associated with the results is as small as the level specified by the contractor?