To make training cost-effective for its small systems customers, Digital Equipment Corporation provides self-paced training packages for several years that can be used by its customers on-site. To control the quality of this training, Digital is now incorporating computer managed instruction (CMI) into some of these packages. This CMI component uses a sequential probability test algorithm that allows tests to vary in length depending upon the learner's skill level. This algorithm assures that the tests' results are statistically reliable while keeping their length as short as possible. (Author)