Learner verification, a process by which publishers monitor the effectiveness of their products and strive to improve their services to schools, is a practice that most companies take seriously. The quality of educational materials may be ensured in many ways: by analysis of sales, through firsthand investigation, and by employing a system of evaluators within the school system. Two case studies are described, one detailing the failure of a product designed to aid in word recognition, the other outlining the use of an independent research group to predict teacher and student acceptance of a flexible instructional packet. While the analysis of educational needs and the pretesting of instructional materials may increase production costs, they can also prevent the proliferation of irrelevant products. (KS)