CC BY-NC-ND 4.0 · Appl Clin Inform 2022; 13(02): 400-409
DOI: 10.1055/s-0042-1744549
Research Article

Improving COVID-19 Research of University Hospitals in Germany: Formative Usability Evaluation of the CODEX Feasibility Portal

Brita Sedlmayr
1   Institute for Medical Informatics and Biometry, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
Martin Sedlmayr
1   Institute for Medical Informatics and Biometry, Carl Gustav Carus Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
Björn Kroll
2   IT Center for Clinical Research, University of Lübeck, Lübeck, Germany
Hans-Ulrich Prokosch
3   Department of Medical Informatics, Biometrics and Epidemiology, Chair of Medical Informatics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
Julian Gruendner
3   Department of Medical Informatics, Biometrics and Epidemiology, Chair of Medical Informatics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
Christina Schüttler
3   Department of Medical Informatics, Biometrics and Epidemiology, Chair of Medical Informatics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
› Author Affiliations
Funding The study was conducted as part of NUM CODEX. NUM CODEX is funded by the German Federal Ministry of Education and Research (BMBF; FKZ 01KX2021).


Background Within the German “Network University Medicine,” a portal is to be developed to enable researchers to query on novel coronavirus disease 2019 (COVID-19) data from university hospitals for assessing the feasibility of a clinical study.

Objectives The usability of a prototype for federated feasibility queries was evaluated to identify design strengths and weaknesses and derive improvement recommendations for further development.

Methods In the course of a remote usability test with the thinking-aloud method and posttask interviews, 15 clinical researchers evaluated the usability of a prototype of the Feasibility Portal. The identified usability problems were rated according to severity, and improvement recommendations were derived.

Results The design of the prototype was rated as simple, intuitive, and as usable with little effort. The usability test reported a total of 26 problems, 8 of these were rated as “critical.” Usability problems and revision recommendations focus primarily on improving the visual distinguishability of selected inclusion and exclusion criteria, enabling a flexible approach to criteria linking, and enhancing the free-text search.

Conclusion Improvement proposals were developed for these user problems which will guide further development and the adaptation of the portal to user needs. This is an important prerequisite for correct and efficient use in everyday clinical work in the future. Results can provide developers of similar systems with a good starting point for interface conceptualizations. The methodological approach/the developed test guideline can serve as a template for similar evaluations.

Protection of Human and Animal Subjects

The study was performed in compliance with the World Medical Association Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects, and was reviewed and approved by the Institutional Review Board at Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg (Germany; approval number: 85_21B). Participants were informed of the contents prior to study participation and voluntarily consented to participate.

Author Contributions

B.S. wrote the first version of the manuscript. B.S. and C.S. planned and conducted the usability study which was supervised by H.-U.P. and M.S.. J.G. held the team lead. B.S., C.S., J.G., and B.K. were significantly involved in the conceptual design and development of the evaluated prototype. C.S. and H.-U.P. were responsible for the recruitment of the participants. B.S. and C.S. analyzed all thinking aloud and interview protocols and the recorded screen videos. All authors read the first version of the manuscript and provided valuable suggestions for changes.

Publication History

Received: 10 September 2021

Accepted: 03 January 2022

Article published online:
20 April 2022

© 2022. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (

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