Background: Self-report measures can guide clinical decisions and are useful when evaluating treatment outcomes. However, many clinicians do not use self-report measures systematically in their clinical practice. Internet-based questionnaires could facilitate administration, but the psychometric properties of the online version of an instrument should be explored before implementation. The recommendation from the International Test Commission is to test the psychometric properties of each questionnaire separately.
Objective: Our objective was to compare the psychometric properties of paper-and-pencil versions and Internet versions of two questionnaires measuring depressive symptoms.
Methods: The 87 participating patients were recruited from primary care and psychiatric care within the public health care system in Sweden. Participants completed the Beck Depression Inventory (BDI-II) and the Montgomery-Åsberg Depression Rating Scale-Self-rated (MADRS-S), both on paper and on the Internet. The order was randomized to control for order effects. Symptom severity in the sample ranged from mild to severe depressive symptoms.
Results: Psychometric properties of the two administration formats were mostly equivalent. The internal consistency was similar for the Internet and paper versions, and significant correlations were found between the formats for both MADRS-S (r = .84) and the BDI-II (r = .89). Differences between paper and Internet total scores were not statistically significant for either questionnaire nor for the MADRS-S question dealing with suicidality (item 9) when analyzed separately. The score on the BDI-II question about suicidality (item 9) was significantly lower when administered via the Internet compared with the paper score, but the difference was small (effect size, Cohen's [d] = 0.14). There were significant main effects for order of administration on both questionnaires and significant interaction effects between format and order. This should not, however, pose a problem in clinical use as long as the administration format is not changed when repeated measurements are made.
Conclusions: The MADRS-S can be transferred to online use without affecting the psychometric properties in a clinically meaningful way. The full BDI-II also seems to retain its properties when transferred; however, the item measuring suicidality in the Internet version needs further investigation since it was associated with a lower score in this study. The use of online questionnaires offers clinicians a more practical way of measuring depressive symptoms and has the potential to save resources.