Self-Determination of Adolescents and Adults with Intellectual and Developmental Disabilities: a Preliminary Study of Validity And Reliability of the New InventoryABSTRACT:
The new educational and rehabilitative policies claim for persons-centered plans, aiming an active citizenship based on self-determination skills. Causal agency theory assumes that action-decisions are made by persons themselves, to control their own life according to their own goals. However, people with intellectual and developmental disabilities (IDD) are still devalued and restricted on these decisions. Although a powerful quality of life predictor and growing interest, self-determination is still less explored. The theory demands robust assessment instruments. This preliminary article aims to analyze the reliability and validity of the Portuguese version of the Self-Determination Inventory (P-SDI), applied to 52 participants aged between 13 and 54 years (22.37±13.7), including 23 females and 29 males, with and without IDD. Content validity indexes (IVC>.90) confirm the representativeness of the items, corroborated by moderate to strong experts’ proportion agreement (≥.76) and Cohen Kappa (.49≤k≤1). Internal consistency and temporal stability are excellent (α≥.91; r≥.90). Correlations are significant (p<.01) between components (r≥.39), components-characteristics (r≥.56), between characteristics (r≥70) and with total (r>.71). The items appear to be organized into three factors, and the invariance of the items is inferred between participants with and without IDD. The P-SDI seems to be an appropriate instrument for assessing self-determination.
KEYWORDS:
Assessment; Intellectual and developmental disability; Self-determination inventory; Validation; Causal agency theory