Comparison between administration via Internet and paper-and-pencil administration of two clinical instruments: SCL-90-R and GHQ-28.

The objective of this study is to compare the results of the Symptom Check List (SCL)-90-R and the General Health Questionnaire (GHQ)-28 administered on paper with the results of administration via Internet. Forty university students were asked to respond to the two questionnaires, first in one format (Internet or paper), and 1 week later in the other format. For the GHQ-28, no statistically significant differences were found between the two forms of presentation, Internet or paper, except in the social dysfunction subscale. In the case of the SCL-90-R, there were differences in the Positive Symptoms Distress Index (PSDI) and in the somatization and obsession-compulsion subscales. The effect of using the two formats in combination was also analyzed. Internal consistency of the instruments is high for both types of presentation (alpha=0.91 in GHQ-28; alpha=0.97 in SCL-90-R). Correlation between the two formats is also high, with values ranging between 0.76 and 0.92, p<0.001, except in the social dysfunction subscale. Finally, correlation between the GHQ-28 and SCL-90-R is also high, for both the paper and Internet results (r=0.88, p<0.01 on paper and r=0.83, p<0.01 via Internet). The differences found should be verified in future research with other types of sample.