Validity and reliability of the movement ability measure: A self-report instrument proposed for assessing movement across diagnoses and ability levels

Background and Purpose Physical therapists lack instruments that assess movement across diagnoses and ability levels while focusing on physical therapy-specific outcomes. This article describes the creation of a Movement Ability Measure (MAM) and initial evidence of validity and reliability. Subjects More than 300 adult volunteers with various movement levels completed the 24-item questionnaire. Methods Item response theory methods were used to create the MAM and gather evidence of content and construct validity, test-retest and other types of reliability, and concurrent validity with the California Functional Evaluation instrument and self-acknowledgement of movement problems. Results The intraclass correlation coefficient for test-retest reliability was .92. Person separation reliability was .98. Correlation (r) with the California Functional Evaluation instrument was .76. Respondents who denied having movement problems perceived a significantly higher level of movement ability than those who claimed to have a little, some, or a lot of movement problems in the preceding week. Discussion and Conclusion The MAM shows promise for documenting perceived movement ability across ability levels and diagnoses.