Programmed instruction is effective because it takes advantage of several important learning principles. First, learning is self-pacedthat is, each trainee proceeds at his own pace. When the presentation speed of the material does not parallel the comprehension speed of the learner, frustration occurs, and the material will not be learned as well as it might. Second, each trainee is actively involved in the learning. This contrasts sharply with the lecture method, where the employee might sit through two hours of lecture without being actively involved. Finally, programmed instruction presents information in small units or chunks, because learning smaller amounts of material is easier than learning larger amounts