Applie behavior analysis (ABA) is the science of applying experimentally derived principles of behavior to improve socially significant behavior. ABA takes what we know about behavior and uses it to bring about positive change (Applied). Behaviors are defined in observable and measurable terms in order to assess change over time (Behavior). The behavior is analyzed within the environment to determine what factors are influencing the behavior (Analysis). Applied behavior is the third of the four domains of behavior analysis, the other three being, behaviorism, experimental analysis of behavior and professional practice of behavior analysis. Applied behavior analysis contributes to a full range of areas including: AIDS prevention, conservation of natural resources, education, gerontology, health and exercise, industrial safety, language acquisition, littering, medical procedures, parenting, seatbelt use, sports, and zoo management and care of animals. ABA-based interventions have gained recent popularity in the last 20 years related to teaching students with autism spectrum disorders.