The relationship among three measures of social functioning in outpatients with schizophrenia.

Deficits in social functioning are a defining characteristic of schizophrenia. Several instruments have been developed to measure social functioning in this population, but there has been little study of the correlation among different instruments. We used the Social Functioning Scale (SFS), the Multnomah Community Ability Scale (MCAS), and the Quality of Life Interview (QOLI) to evaluate 72 stable outpatients with schizophrenia. Results of canonical analyses indicate a significant but limited relationship between each set of measures. The largest overlap was between the QOLI and the SFS (R2c = .597) with less shared variance found between the SFS and the MCAS (R2c = .520) and between the MCAS and the QOLI (R2c = .335). Although the instruments share some common content. the instruments measure different aspects of social functioning. A consensus is needed about how to define and measure social functioning in this population.