Objective
The purpose of this study was to determine the validity and the reliability of the Activity Index to ascertain its value in the functional evaluation of stroke patients.

Method
The Activity Index consists of sixteen variables divided into three main parts(mental capacity, motor activity, and ADL function) with a total value ranging from 16 to 92 points. A group of 96 stroke patients were included in this study. To determine the validity, kappa statistics between the Functional Independence Measure and the Activity Index were measured.

Results
In the validity study, the kappa statistics between the Functional Independence Measure and Activity Index were 0.79 and 0.84 for an initial total score and a discharge total score respectively, indicating a reasonable agreement between the two tests. In the reliability study, the Cronbach's alpha coefficient was 0.97 for the total score indicating a good internal consistency.

Conclusion
The Activity Index demonstrated an acceptable validity and reliability for the evaluation of functional capacity of stroke patients in clinical practice.