Validation of the brief Quality of Life Interview (QoLI): I. Internal structure

Background: This paper reports a study of the psychometric properties of the brief version of Lehman’s Quality of Life Interview (QoLI), an instrument which evaluates both subjective and objective components of quality of life. Method: One hundred and twenty eight patients who met DSMIV criteria for schizophrenia were evaluated with the brief QoLI in its French version. The internal structure of the QoLI was explored in terms of an analysis of items, a study of correlations between items and item dimensions, and a principal component analysis of the subjective and item dimensions, and a principal component analysis of the subjective and objective domains. The internal consistency of the scale was evaluated by Cronbach’s α. Results: The individual items all discriminated strongly between subjects. Items showed high correlations with the subscales of which they were part, and much lower correlations with the other subscales, confirming the relevance of the domains defined a priori, particularly for the subjective domains. Principle component analysis also strongly supported the separation between the different domains of quality of life. Analysis of internal consistency did not reveal items that could be dropped from the interview