The Gordon Diagnostic System (GDS) is a unique assessment device that aids in the diagnosis of attention deficits in both children and adults. It provides extensively standardized (over 1600 children and adults), objective data about an individual’s ability to sustain attention and exert self-control. This practical, reliable, and well-researched technique enhances the accuracy and relevance of a comprehensive evaluation for attention deficits and impulsiveness. It is completely portable, sturdy, extremely easy to use, and has unlimited administrations. A widely used and respected modality, the GDS has become the established standard for laboratory measurement of attention and self-control. It is also used to help monitor the effects of pharmacotherapy.