In 1937, research was initiated to develop a questionnaire that would aid physicians in evaluating the psychologic functioning of patients. The questionnaire quickly proved to be useful and became, as the Minnesota Multiphasic Personality Inventory (MMPI), the most widely used and thoroughly researched objective personality-assessment instrument. In 1959, the first computerized scoring and interpretative system for the MMPI was developed at the Mayo Clinic. During the 50 years that the MMPI has been used, however, our society has changed considerably. Therefore, a new normal contemporary reference sample of adults was obtained by Mayo Clinic investigators in 1983. Significant changes in response patterns were observed in comparison with the original norms, and new tables, based on normalized T scores rather than the linear transformation procedures of the past, were developed; these were incorporated into the Mayo Clinic MMPI scoring and interpretative system in 1984. Subsequently, a companion study of contemporary normal adolescents (691 girls and 624 boys) also showed significant changes in response patterns in comparison with the original norms. In addition, MMPI profiles from contemporary normal adolescents continue to differ from those of contemporary normal adults, similar to the differences noted between these two groups in the past. Data from these contemporary normal adolescents were used to develop new adolescent norms, which were incorporated into the Mayo Clinic scoring and interpretative system for the MMPI in January 1988.