There are many factors that contribute to the long-term treatment outcome of a child with autism. Some of these factors can be controlled and some cannot.

Cognitive Ability Research has shown that children starting at the same age, with the same intensity, consistency of treatment, and same treatment choice, may have different treatment outcomes. This, we believe, is due to the individual cognitive ability of the child. Some children may learn vary fast and others may learn slower. Some children may find it difficult to learn abstract concepts, while others may become fluent in all areas.
Treatment Age It has been well documented that children with ASD benefit the most in the early years. Early intervention is critical to ensure the maximum progress. This is not to say that older children do not benefit from treatment; they do, however as children get older the developmental gaps become wider and more difficult to catch up. Thus, it is recommended that intervention be done as early as possible.
Quality of Treatment It is critical to ensure that the treatment your child receives is of a high quality. There is tremendous variability in the quality of treatment services. Providers may claim to provide treatment services without the proper training or quality control. Professional and well-qualified treatment Therapists should receive ongoing extensive training and supervision by experts in the field. Your program should be as good as the person who designs the curriculum and the people that implement it.
Treatment Intensity Children with autism face the formidable challenge of not only trying to catch up the developmental gaps that already exist but also they need to keep up their learning pace with their peers to ensure that the gaps do not widen. For example, a child who has a 2-year delay in language may only learn one year of language in a year. This would normally be ideal as it represents a lot of progress. However, the two-year delay still exists because the child is older and his peers have acquired another year of knowledge. In order to actually catch up, the student needs to learn more than one year of language in a year. If the student caught up 1.5 years of language every year, it would then take him or her 4 years to finally catch up with peers. This then presents a real challenge. Given the multitude of deficits that are often present with autism, it is critical that all areas are taught intensively and systematically. It is not unlike taking a child and training him or her to become an Olympic swimmer. Spending one hour a week on one of the deficit areas that is 2 years behind is unlikely to yield the results we may wish for. Research has consistently shown that a high volume of hours is ideal to maximize a child’s learning progress.
Consistency In order to maximize program progress, it is critical that the whole treatment team provides service in a consistent approach. If the student is doing sign language in the morning and using pictures to communicate in the afternoon, it is likely to result in confusion on the part of the student. If a number of practitioners are working together, it is then essential that they meet regularly to formulate a comprehensive plan so that the treatment can be consistent. This is also true for the consistency between parents and the treatment team. Parents need to be involved and develop knowledge and expertise in treatment so as to help their child learn and generalize skills.