Convergent validation of quality of life assessments for persons with severe mental illnesses.

The impact of interventions on the quality of life (QOL) experienced by persons with severe and persistent mental illnesses (SPMI) has attracted considerable political, clinical and research attention over the past decade, and continues to do so. This study examines the convergent validity of two commonly used QOL measures for this group of patients, the Lehman Quality of Life Interview and the Heinrichs-Carpenter Quality of Life Scale, computing the correlations between comparable constructs from the two measures administered at the same time and 2 months apart. Correlations were positive and significant although low to moderate in magnitude. Considering the considerable differences in the methods of assessment employed by the two measures, the lack of precise congruence between their constructs, and the 2-month time interval, these findings support their convergent validity. Various conceptual issues regarding the validity and interpretation of QOL assessments for persons with SPMI are discussed.