Scale for assessing functional impairment in adults with asthma.

Improved outcome measures for asthma research, especially measures of functional status and quality of life, have become increasingly important. This research describes one such measure, the University of Alabama at Birmingham (UAB) Functional Impairment Scale. This scale consists of eight items to assess the impact of asthma on various aspects of daily living. The psychometric properties of the UAB Scale were assessed in two samples. The coefficient alpha reliabilities were high in both samples (.83 and .84), and the item-total correlations indicated all items were measuring the same trait. The score distributions covered the entire range of possible scores, and the central tendencies and dispersions confirmed the presence of enough variation to detect differences in functional impairment among individuals. Correlations between the UAB Scale and other asthma-related measures support construct validity. All of these results support the potential usefulness of the UAB Scale.