An interview designed for use with the parents of children or adults who are being assessed for an autism spectrum diagnosis. The ADI comprises questions about the offspring’s current skills and behaviours, as well as how these behaviours were manifested at age four to five years or at any point during development. The original version of the instrument (the ADI) was often used to verify diagnoses for research purposes. The revised version, designed for diagnosis in clinical settings, was published in 2003.