INFLUENCE OF INSTRUMENTAL ACTIVITIES OF DAILY LIVING ASSESSMENT METHOD ON JUDGMENTS OF INDEPENDENCE

Objective: Occupational therapists frequently evaluate instrumental ac tivities of daily living (IADL) performance with interviews and observ ation of simulated tasks. This study examined the congruence of judgme nts of independence when comparing task performance assessed by interv iew and simulation with task performance assessed by observation in th e natural environment. Method: Twenty persons with severe mental illne ss were selected through convenience sampling and evaluated on two IAD L tasks (making a purchase in a store and using the bus). The particip ants were evaluated on each task with two methods of assessment: inter view and simulation and observation in the natural environment. Result s. Results indicated inconsistent performance across assessment approa ches and tasks and supported the importance of considering contextual features in understanding the complexity of performance in the natural environment. A trend toward false positives was found in which severa l participants were judged independent on the IADL assessment but coul d not perform the same tasks in the natural environment. Conclusion. O ccupational therapists should be cautious when making judgments of ind ependence on the basis of interview and observation of simulated tasks . Evaluating IADL performance in the persons' natural environment may provide more accurate information.