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BRIEF RESEARCH REPORT article
Front. Psychol.
Sec. Quantitative Psychology and Measurement
Volume 16 - 2025 | doi: 10.3389/fpsyg.2025.1526181
Psychometric evaluation and community norms of the GAD-7, based on a representative German sample
Provisionally accepted
Sören Kliem 1*
Cedric Sachser 2
Anna Lohmann 1
Dirk Baier 3*
Elmar Braehler 4
Jörg Michael Fegert 2
Harald Gündel 2- 1 Ernst-Abbe-Hochschule Jena, Jena, Germany
- 2 Ulm University Medical Center, Ulm, Germany
- 3 Zurich University of Applied Sciences, Winterthur, Zürich, Switzerland
- 4 Leipzig University Medical Center, Leipzig, Germany
The Generalized Anxiety Disorder (GAD-7) scale is a reliable and valid instrument for the assessment of generalized anxiety symptoms in the general and clinical populations. The aim of the present study is to investigate its psychometric properties in a large sample representative for the adult population of the Federal Republic of Germany (N = 2519) and to provide updated population norms. We assessed item characteristics such as item means, standard deviations as well as inter-item correlations. Construct validity was assessed by correlating the scales with scales assessing depression, anxiety and somatization (PHQ-9, BSI-18). Internal consistency was assessed via coefficient omega. Factorial validity was assessed via confirmatory factor analysis of the assumed one factorial model. Measurement invariance was investigated via multi-group confirmatory factor analyses across gender and age. Population based norms for the total sample as well as for various age-groups are provided. Our results attested sound psychometric properties for the GAD-7 in the general population in terms of internal consistency and construct validity. Measurement invariance analyses indicate that measurements obtained with the GAD-7 can be compared across gender and age. The updated norms provide a useful basis for clinical practice as well as epidemiological research.
Keywords: GAD-7, Generalized anxiety, Self-report questionnaire, Population norms, Psychometrics, Measurement invariance
Received: 11 Nov 2024; Accepted: 28 Feb 2025.
Copyright: © 2025 Kliem, Sachser, Lohmann, Baier, Braehler, Fegert and Gündel. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Sören Kliem, Ernst-Abbe-Hochschule Jena, Jena, Germany
Dirk Baier, Zurich University of Applied Sciences, Winterthur, 8401, Zürich, Switzerland
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