A measurement of self-determination for people with intellectual disability: description of the AUTODDIS scale and evidences of reliability and external validity.

Appropriate supports and instructional practices contribute to the development of self-determination. Also, research shows that the promotion of skills related to self-determination has been linked to the achievement of desired outcomes over the different life stages. Advances in self-determination require the development of assessment instruments because there is a reciprocal relationship between assessment and instruction. The purpose of this paper is to provide a description of the AUTODDIS Scale, along with evidence of its reliability and external validity. A sample of 541 people with intellectual disabilities aged from 11 to 40 was used to validate the scale. The reliability results indicate that the AUTODDIS Scale shows high internal consistency. The total score and subscale scores indicate moderate inter-rater reliability. The scores were also moderately to highly associated with other related measures of self-determination and quality of life (QoL). Our results demonstrate that consistent and valid information can be obtained from the AUTODDIS Scale.