The importance of modeling method effects: resolving the (uni)dimensionality of the loneliness questionnaire.

This study sought to resolve the dimensionality of the Loneliness Questionnaire (LQ; Asher, Hymel, & Renshaw, 1984) by applying recommended confirmatory factor analytic procedures that control for method effects (Brown, 2003). This study was needed given that inconsistent findings have been reported recently regarding the structure of this instrument (Bagner, Storch, & Roberti, 2004) and all models to date have not accounted for method effects due to the non-reversed-worded and reversed-worded items of this instrument. Using a large sample of youth in Grades 2 through 12 (N = 11,725), we compared the previously reported 1- and 2-factor models with a newly posited 1-factor model that incorporated correlated error terms to account for method effects. We found that the 1-factor model that included correlated error terms fit the data best, and that this factor structure evidenced measurement invariance across boys and girls in childhood, but not in adolescence. The meaning of the LQ indicators was also consistent for boys across development, but evidenced differences for girls in childhood versus adolescence. More generally, it was demonstrated that modeling method effects is vital to accurately understanding the dimensionality of loneliness when reversed-worded and non-reversed-worded items are used as indicators. The measurement and clinical implications of these findings are discussed.