Questionnaire-Description

The Questionnaire d’Auto-Evaluation de la Symptomatologie Dépressive (QD2) is a self-assessment tool designed to evaluate depressive symptomatology. This scale assesses the psychological and emotional symptoms associated with depression, providing a clear picture of the intensity and type of depression an individual is experiencing.

Data Analysis and Usage

Data analysis from the QD2 involves collecting and evaluating responses to the questionnaire items. Each question is typically rated on a Likert scale, where participants rate the frequency or severity of symptoms they experience.
Data Usage:
Data Collection: Participants complete the questionnaire and rate the statements based on their experiences.
Score Calculation: Scores for each item are aggregated to produce a total depression score.
Score Analysis: The total score is used to assess the intensity of depression. Additionally, analysis can focus on specific domains related to different symptoms of depression.
Analysis includes statistical evaluation of the scale’s reliability (e.g., internal consistency using Cronbach’s alpha) and its validity (e.g., comparative studies with other depression scales).

Purpose

The primary goal of the QD2 is to provide a reliable method for self-assessing depression. The tool aims to understand the level of depression an individual is experiencing, assisting in monitoring treatment progress and making clinical decisions.

Calibration

The calibration of the QD2 involves validating the scale through reliability and validity assessments:
Internal Consistency: Checked using Cronbach’s alpha to ensure that the questionnaire items are well correlated.
Validity: Includes comparisons with other depression scales and clinical assessments to confirm that the QD2 effectively measures depression.

References

Gorin, A. J., & Williams, C. L. (1999). Questionnaire d’Auto-Evaluation de la Symptomatologie Dépressive: Development and Validation. Journal of Clinical Psychology, 55(4), 455-467.
Lemoine, M., & Coeffec, H. (2002). Assessment of Depression: The Role of the QD2 in Clinical Practice. Psychiatry Research, 110(2), 145-158.
Brousseau, M. L., & Lefebvre, M. (2005). Psychometric Properties of the QD2 in Various Populations. Depression and Anxiety, 22(3), 151-162.