This paper identifies problems in drug testing accuracy that may arise in small business environments in which job applicants are subjected to drug tests, and suggests a method for dealing with the problems. Relevant concepts of drug-test accuracy are reviewed These concepts are incorporated in Bayesian analyses of data from specific workplace-applicant populations, and accuracy levels to be expected in testing of applicants in such workplaces are identified The conclusion of this analysis is that seemingly accurate tests for abused drugs can be inaccurate to a disturbingly high degree, particularly under circumstances likely to be present in many small business drug-testing programs. A method by which these inaccuracies can be avoided is suggested
