abstract
Background: The 30-item USDI is a self-report measure that assesses depressive symptoms among
university students. It consists of three correlated three factors: lethargy, cognitive–emotional and
academic motivation. The current research used confirmatory factor analysis to asses construct validity
and determine whether the original factor structure would be replicated in a different sample.
Psychometric properties were also examined.
Method: Participants were 1148 students (mean age 22.84 years, SD¼6.85) across all faculties from a
large Australian metropolitan university. Students completed a questionnaire comprising of the USDI, the
depression anxiety stress scale (DASS) and Life Satisfaction Scale (LSS).
Results: The three correlated factor model was shown to be an acceptable fit to the data, indicating sound
construct validity. Internal consistency of the scale was also demonstrated to be sound, with high
Cronbach alpha values. Temporal stability of the scale was also shown to be strong through test-retest
analysis. Finally, concurrent and discriminant validity was examined with correlations between the USDI
and DASS subscales as well as the LSS, with sound results further supporting the construct validity of the
scale. Cut-off points were also developed to aid total score interpretation.
Limitations: Response rates are unclear. In addition, the representativeness of the sample could be
improved potentially through targeted recruitment (i.e. reviewing the online sample statistics during
data collection, examining the representativeness trends and addressing particular faculties within the
university that were underrepresented).
Conclusions: The USDI provides a valid and reliable method of assessing depressive symptoms found
among university students.