Rater training and the maintenance of the consistency of ratings are critical to ensuring reliability of study measures and sensitivity to changes in the course of a clinical trial. The Positive and Negative Syndrome Scale (PANSS) has been widely used in clinical trials of schizophrenia and other disorders and is considered the “gold standard” for assessment of antipsychotic treatment efficacy. The various features associated with training and calibration of this scale are complex, reflecting the intricacy and heterogeneity of the disorders that the PANSS is used to evaluate. In this article, the authors review the methods for ensuring reliability of the PANSS as well as a proposed trajectory for its use in the future. An overview of the current principles, implementation, technologies, and strategies for the best use of the PANSS; tips for how to achieve consistency among raters; and optimal training practices of this instrument are presented.