About

After previously being a student assistant at the working group Biometry in Molecular Medicine (led by Prof. Anne-Laure Boulesteix), I joined the group as a PhD student in January 2020. My main focus is on researcher degrees of freedom and over-optimism in gene (set) analysis and method performance evaluation.

I obtained a Bachelor's Degree (B.Sc.) and a Master's Degree (M.Sc.) in Statistics from the Ludwig-Maximilians-University Munich.

Research Interests

• Researcher degrees of freedom and over-optimism
• Differential expression analysis and gene set analysis
• Method performance evaluation

Publications 

Submitted articles

• C. Sauer, A.-L. Boulesteix, L. Hanßum, F. Hodiamont, C. Bausewein, T. Ullmann, 2024. Beyond algorithm hyperparameters: on preprocessing hyperparameters and associated pitfalls in machine learning applications. arXiv preprint arXiv:2412.03491.

Peer-reviewed articles                           

• M. Wünsch, C. Sauer, M. Herrmann, L. C. Hinske, A.-L. Boulesteix, 2025. To tweak or not to tweak. How exploiting flexibilities in gene set analysis leads to over-optimism. Biometrical Journal, 67(1):e70016.
• E. Boehm, C. Sauer, A. Baur-Melnyk, J. T. Biebl, S. Harada, B. Wegener, E. Kraft, R. Stahl, I. Feist-Pagenstert, 2024. Real-life effects of pharmacological osteoporosis treatments on bone mineral density by quantitative computed tomography. Journal of Bone and Mineral Metabolism, 42(6):741–753.
• M. Wünsch, C. Sauer, P. Callahan, L. C. Hinske, A.-L. Boulesteix, 2024. From RNA sequencing measurements to the final results: A practical guide to navigating the choices and uncertainties of gene set analysis. WIREs Computational Statistics, 16(1):e1643.
  
• C. Nießl, S. Hoffmann, T. Ullmann, A.-L. Boulesteix (2024). Explaining the optimistic performance evaluation of newly proposed methods: A cross-design validation experiment. Biometrical Journal, 66(1):2200238.
  
• C. Nießl, M. Herrmann, C. Wiedemann, G. Casalicchio, A.-L. Boulesteix (2022). Over-optimism in benchmark studies and the multiplicity of design and analysis options when interpreting their results. Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery, 12(2):e1441.
• C. Nießl, A.-L. Boulesteix, J. Oh, K. Palm, et al. (2022). Relationship between age at initiation of cysteamine treatment, adherence with therapy, and glomerular kidney function in infantile nephropathic cystinosis. Molecular Genetics and Metabolism, 136(4):268-273.
• K. Hohenfellner, C. Nießl, D. Haffner, J. Oh, C. Okorn, K. Palm, K.-P. Schlingmann, S. Wygoda, W. A. Gahl (2022). Beneficial effects of starting oral cysteamine treatment in the first 2 months of life on glomerular and tubular kidney function in infantile nephropathic cystinosis. Molecular Genetics and Metabolism, 136(4):282-288.