Welcome to my website!

I am currently an Assistant Professor of Health Statistics (“Juniorprofessor” in German) and an Emmy Noether junior research group leader at Karlsruhe Institute of Technology, Germany. I am moreover affiliated with the Heidelberg Institute for Theoretical Studies and serve as a PI in the Helmholtz Information and Data Science School for Health.

You can also find me on my institutional website, Google Scholar and mastodon.

My email address is [my first name].[my last name]@kit.edu.

News

• My group is co-organizing a one-day workshop on Mathematical Modelling of Antimicrobial Resistance on 10 June 2026, jointly with the Quantitative and Predictive Infectious Disease Epidemiology Group at University Medical Center Freiburg.
• The second South-West German Infectious Disease Modelling Workshop took place in Heidelberg on 9 December 2025, co-organized by the CSIDLab at Heidelberg University and my group.

Research interests

Most of my group’s research is centered around statistical methods for infectious disease epidemiology, but we also do some more theoretical work as well as statistical consulting. The following are our main topics (click to expand).

Multi-model nowcasting and forecasting of infectious disease spread

Over time, we have operated various collaborative platforms for real-time nowcasting and short-term forecasting of infectious diseases (most recently the RESPINOW Hub). We also work on methodological topics in this domain as part of my Emmy Noether grant.

Selected papers:

• Ribeiro Amaral AV, Wolffram D, Moraga P, Bracher J (2025). Post-processing and weighted combination of infectious disease nowcasts. PLOS Computational Biology.
• Sherratt K, Gruson H, […], Bracher J, Funk S (2023). Predictive performance of multi-model ensemble forecasts of COVID-19 across European nations. Elife.
• Wolffram D, Abbott, […], Bracher J (2023). Collaborative nowcasting of COVID-19 hospitalization incidences in Germany. PLOS Computational Biology.
• Cramer EY, Ray EL, Lopez VM, Bracher J et al (2022). Evaluation of individual and ensemble probabilistic forecasts of COVID-19 mortality in the US. Proceedings of the National Academy of Sciences.
• Bracher J, Wolffram D, Deuschel J, et al (2021). A pre-registered short-term forecasting study of COVID-19 in Germany and Poland during the second wave. Nature Communications.

Forecast evaluation

We are interested in principled and interpretable evaluation methods for probabilistic forecasts in infectious disease epidemiology and other fields.

Selected papers:

• Resin J, Wolffram D, Bracher J, Dimitriadis R (2026). Shift-Dispersion Decompositions of Wasserstein and Cramer Distances. Statistical Science.
• Bracher J, Rüter L, Krüger F, Lerch S, Schienle M (2024). Direction Augmentation in the Evaluation of Armed Conflict Predictions. International Interactions (subscription needed; see preprint here.).
• Bosse NI, Abbott S, Cori A, van Leeuwen E, Bracher J, Funk S (2023). Scoring epidemiological forecasts on transformed scales. PLOS Computational Biology.
• Bracher J, Ray EL, Gneiting T and Reich NG (2020) Evaluating epidemic forecasts in an interval format. PLOS Computational Biology.
• Bracher J (2019). On the multibin logarithmic score used in the FluSight competitions. Proceedings of the National Academy of Sciences.

Simple statistical methods for disease surveillance.

Many types of statistical analyses in infectious disease surveillance are recurrent and need to be run on many time series without specific tuning. This creates a need for simple and robust methods. We are interested in the properties and improvement of such methods.

Selected papers:

• Johnson KE, Tang ML […], Bracher J, Abbott S (2026). Baseline nowcasting methods for handling delays in epidemiological data. Wellcome Open Research.
• Nemcova B, Goldstein IH, Sebastian J, Minin V, Bracher J (2025). Unjustified Poisson assumptions lead to overconfident estimates of the effective reproductive number. Preprint.
• Bracher J, Littek JM (2025). A statistical assessment of influenza intensity thresholds from the moving epidemic and WHO methods. Journal of the Royal Statistical Society Series A.

Count time series modelling

Count time series arise commonly in epidemiology and many other fields. We develop time series models tailored to such data.

Selected papers:

• Bracher J, Nemcova B (2025). A unifying class of compound Poisson integer-valued ARMA and GARCH models. Scandinavian Journal of Statistics.
• Bracher J, Held L (2021). A Marginal Moment Matching Approach for Fitting Endemic-Epidemic Models to Underreported Disease Surveillance Counts. Biometrics (subscription needed; see preprint here).
• Bracher J, Held L (2022). Endemic-epidemic models with discrete-time serial interval distributions for infectious disease prediction. International Journal of Forecasting (subscription needed; see preprint here).

Statistical consulting

We collaborate with researchers from various disciplines, providing statistical expertise for applied work.

Selected papers:

• Schanzer S, Koch M, […], Bracher J, Müller C (2022). Analysis of pesticide and persistent organic pollutant residues in German bats. Chemosphere.
• Peter M, Nemcova B, […], Bracher J, Heurich M, Müller C (2026). Deer as sentinels of emerging environmental pollution: Assessing contamination patterns and seasonal variations. Science of the Total Environment.

Teaching

I teach various courses at KIT, a little different each semester (mainly on regression, forecasting and epidemic modelling). Please check the current Vorlesungsverzeichnis. I also supervise BSc and MSc theses related to my research topics (see above). Don’t hesitate to get in touch if you are a student at KIT.

Short Bio

• Current position: Assistant professor of Health Statistics, Karlsruhe Institute of Technology.
• Previous positions:
  • Postdoctoral researcher, Chair of Statistics and Econometrics, Karlsruhe Institute of Technology.
  • Research assistant, Epidemiology, Biostatistics and Prevention Institute, University of Zurich.
• Education:
  • PhD Epidemiology and Biostatistics, University of Zurich. Thesis title: Statistical modelling and forecsting of infectious disease surveillance counts. Supervisor: Leonhard Held.
  • MSc Statistics, LMU Munich.
  • BA Sociology / Political Science, LMU Munich.
  • BSc Statistics, LMU Munich.