At the first visit, the study will be explained in detail. Adults will be asked to provide written informed consent. Parents or guardians of individuals under the age of 18 years old will provide written informed consent on behalf of the minor. Individuals between the age of 7 and 18 years of age will also provide their written assent. All consents and assents will be obtained prior to any study procedure being performed. Following consent, a brief medical history, including current medications the subject is taking, will be obtained. Subjects will complete a standard self-assessment questionnaire, appropriate for age, to screen for presence of ADHD. Subjects will not be excluded from the study based on responses to the questionnaire but their results will be considered in the analysis of study data. All subjects will take the appropriate version; Child (ages 6 -12.11), Adolescent (ages 13 - 19.11), or Adult (ages 20 - 79.11) of the 15-minute Quotient® System iPad Test.