Quality of self-reported measures of functional status.
In the Zutphen Elderly Study, self-reported functional status was measured with the self-administered 13-item WHO-questionnaire on Activities of Daily Living. A hierarchic disability-scale was constructed based on basic activities of daily living (e.g. walking indoors), mobility-related (e.g. moving outdoors) and instrumental activities of daily living (e.g. preparing meals). The reproducibility of the self-reported disabilities was fair to good.
Quality of the performance-based measures of functional status
Performance-based measures of functional status are more objective than self-reported measures. A score from performance-based limitations was based on the results of four tests: standing balance, walking speed, ability to rise from a chair, and external shoulder rotation. Three of the four performance tests were highly reproducible, the shoulder rotation test was not.