The validity of adding new tasks to the assessment of motor and process skills.

OBJECTIVE Twenty-one new activities of daily living (ADL) tasks were evaluated for the validity of their inclusion into the Assessment of Motor and Process Skills (AMPS). METHOD Data from 1,484 participants who performed at least one new AMPS task were analyzed to determine whether the new tasks (a) fit the AMPS many-faceted Rasch (MFR) model and (b) increase the range of the AMPS motor and process skill scales. RESULTS Twenty of the 21 new tasks fit the MFR model. The AMPS motor scale was increased by .25 logit at the easier end of the scale and by .30 logit at the more difficult end of the scale. The AMPS process scale was increased by .14 logit at the easier end of the scale. The more difficult end of the AMPS process scale did not increase. CONCLUSION These findings support the validity of adding 20 new tasks into the AMPS. The new tasks provide the following benefits for testing clients whose ADL ability levels are at the lower or higher ends of the AMPS motor or process skill scales: (a) potential for less error when estimating the ADL ability measures, (b) more task choices, and (c) more face-valid tasks for testing men.