ABA is a scientific approach that is used to identify environmental variables that reliably influence socially significant behaviours, and uses that knowledge to make ethical desirable changes. When ABA is used in the context of treating young children it is referred to as Early Intensive Behaviour Intervention (EIBI). Discrete Trial Training (DTT) is a type of EIBI . In a study published in 2007 it was demonstrated that while the costs of EIBI were higher than special education per year, EIBI is cheaper in the long term. EIBI lasts for an average of 3 years for a substantial number of children who will mainstream without the need for additional special education funds in childhood, and on average these children will become productive adults. Studies that have evaluated EIBI have highlighted positive impacts on parents. A study published in 2009 supports the clinical implication that EIBI at present should be an intervention of choice for children with ASD. Three approaches that make use of the principles of ABA are: Verbal Behaviour (VB), Positive Behaviour Support (PBS) and Pivotal Response Training (PRT). In addition to these ABA based therapies, ?ASK also uses Social Skills training and multidisciplinary team working.