Research suggests that there are not overall practice effects on the ADOS-2. Although children who are given the ADOS-2 repeatedly (such as every month or so) may become more familiar with particular tasks (e.g., they may get better at following a birthday party routine), their scores are generally not affected, and the diagnosis as a whole does not seem to be impacted. The scoring of the ADOS-2 emphasizes the child’s spontaneous initiations and responses to the examiner’s behavior, as opposed to scoring of the tasks themselves. Therefore, it makes sense that becoming more familiar with an activity should not change the child’s scores. Similar observations have been made when the ADOS-2 is used repeatedly with adults with ASD; they may become more familiar with the tasks, but they are consistently classified on the algorithm as having ASD.

Although ADOS-2 scores do not change much on repeated administration, ideally it is better if examinees do not learn the tasks. There should always be good clinical reasons for repeating the ADOS-2, especially if it is administered more than twice within a brief interval. If it is known that the ADOS-2 is going to be repeated during a short period of time, the examiner may want to decide in advance to use different materials from the kit each time when possible (e.g., use one book one time and another the next).