Internet vs. Paper and Pencil Administration of Questionnaires Commonly Used in Panic/Agoraphobia research

The aim of this study was to investigate the psychometric properties of Internet adminstrated questionnaires used in panic research. Included were 494 persons who had registered for an Internet-based treatment program for panic disorder (PD). Participants were randomly assigned to fill in the questionnaires either on the Internet or the paper-and-pencil versions, and then to fill in the same questionnaires again the next day using the other format. The included questionnaires were: Body Sensations Questionnaire (BSQ; Chambless, Caputo, Bright, & Gallagher, 1984), Agoraphobic Cognitions Questionnaire (ACQ; Chambless et al., 1984), Mobility Inventory (MI; Chambless, Caputo, Jasin, Gracely, & Williams, 1985), Beck Anxiety Inventory (BAI; Beck, Epstein, Brown, & Steer, 1988), Beck Depression Inventory II (Beck & Steer, 1996), Quality of Life Inventory (QOLI; Frisch, Cornell, Villanueva, & Retzlaff, 1992), and Montgomery Åsberg Depression Rating Scale (MADRS; Svanborg & Åsberg, 1994). Results showed largely equivalent psychometric properties for the two administration formats (Cronbach between .79 and .95). The results showed strong significant correlations between the Internet and the paper-and-pencil versions. Analyses of order effects showed an interaction effect for the BSQ and the MI (subscale Accompanied), a main effect was identified for ACQ, MI-Alone, BAI and BDI II. However, in contrast to previous research, Internet version did not consitently generate higher scores and effect sizes for the differences were generally low. Given the presence of interaction effect, we recommend that adminstration format should be stable in research across measurement points. Finally, the findings suggest that Internet versions of questionnaires used in PD research can be used with confidence.