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Prof. Dr. rer. nat. Willi Sauerbrei

Photo - Willi Sauerbrei 
Phone: ++49 (0)761 203-6669
Fax: ++49 (0)761 203-5002
Hebelstr. 11
Room no.: NN

Research Interests


  • Multivariable model-building in regression models (MFP)
  • Model validation
  • Dose-response curves, emphasize on Fractional Polynomials
  • Resampling methods
  • Model uncertainty
  • Time-varying effects in survival data
  • Meta-analyses and EBM
  • Diagnostic studies
  • High-dimensional data
  • Reporting of studies
  • Guidance for planning and analysis of observational studies
    - STRengthening Analytical Thinking for Observational Studies
       The STRATOS initiative (STRATOS)



  • Breast cancer: diagnosis and therapy
  • Evidence based medicine
  • Interactions between treatment and continous markers



German Research foundation

  • Increasing clinical usefulness of gene signature prediction rules through simplification and validation
  • Generalisation of the fractional polynomial procedure for semi-continuous variables in epidemiology and clinical research
  • Statistical modeling of complex multivariable functional relationships
  • Assessment of time-varying long-term effects of therapies and prognostic factors
  • Model selection uncertainty and its influence on statistical prognostic and diagnostic models
  • Statistical methods for the development and validation of prognostic models in oncology

Selected Publications

Book: P. Royston, W. Sauerbrei. 'Multivariable Model - Building: A Pragmatic Approach to Regression Anaylsis based on Fractional Polynomials for Modelling Continuous Variables'. Wiley 2008


Winzer KJ., Buchholz A., Schumacher M., Sauerbrei W. (2016): The prognostic ability of the Nottingham Prognostic Index in breast cancer: better use of standard information and clinical relevance. PLoS ONE, 11(3):e0149977, DOI: 10.1371/journal link

De Bin R., Janitza S., Sauerbrei W., Boulesteix AL. (2016): Subsampling versus bootstrapping in resampling-based model selection for multivariable regression.  Biometrics, DOI: 10.1111/biom12381

Dunkler D., Sauerbrei W. and Heinze G. (2016): Global, Parameterwise and Joint Post-Estimation Shrinkage. Journal of Statistical Software, 69:8, DOI: 10.1867/jss.v069.i08

Sauerbrei W, Abrahamowicz M, Altman DG, le Cessie S and Carpenter J on behalf of the STRATOS initiative. (2014) STRengthening Analytical Thinking for Observational Studies: the STRATOS initiative. Statistics in Medicine, 33: 5413-5432, DOI: 10.1002/sim.6265 link

Kasenda B., Sauerbrei W., Royston P., Briel M. 2014, (2014): Investigation of continuous effect modifiers in a meta-analysis on higher versus lower PEEP in patients requiring mechanical ventilation - protocol of the ICEM study. Systematic Reviews, 3:46. DOI: 10.1186/2046-4053-3-46 link

Royston P., Sauerbrei W. (2014): Interaction of treatment with a continuous variable: simulation study of power for several methods of analysis. Statistics in Medicine, 33: 4695-4708, DOI: 10.1002/sim.6308

Royston P., Sauerbrei W. (2013): Interaction of treatment with a continuous variable: simulation study of significance level for several methods of analysis. Statistics in Medicine, 32(22):3788-3803. DOI: 10.1002/sim.5813.

Hingorani A.D., van der Windt D., Riley R.D., Abrams K., Moons K.G.M., Steyerberg E.W., Schroter S., Sauerbrei W., Altman D.G., Hemingway H. for the PROGRESS Group (2013): Prognosis research strategy (PROGRESS) 4: Stratified medicine research. British Medical Journal, 2013; 346. DOI: 10.1136/bmj.e5793. link

Van Houwelingen H.C., Sauerbrei W. (2013): Cross-validation, shrinkage and variable selection in linear regression revisited. Open Journal of Statistics, 3: 79-102. DOI: 10.4236/ojs.2013.32011 link

Binder, H., Sauerbrei, W., and Royston, P. (2013): Comparison between splines and fractional polynomials for multivariable model building with continuous covariates: a simulation study with continuous response. Statistics in Medicine. 32:2262-2277. DOI: 10.1002/sim.5639

Altman D.G.; McShane L.M.; Sauerbrei W.; Taube S.E. (2012): Reporting recommendations for tumor marker prognostic studies (REMARK): explanation and elaboration. In: PLoS Med 9(5): E 1001216 and in BMC Med 10 (1), 51. link

Abo-Zaid G., Sauerbrei W., Riley R.D. (2012): Individual participant data meta-analysis of prognostic factor studies: state of the art? In: BMC Med Res Methodol 12 (1), 56. link

Schumacher M., Holländer N., Schwarzer G., Binder H., Sauerbrei W. (2012): Prognostic Factor Studies, in: Crowley, J., Hoering, A., Handbook of Statistics in Clinical Oncology, Third Edition: Chapman and Hall/CRC, 415-470.

Becher H., Lorenz E., Royston P., Sauerbrei W. (2012): Analysing covariates with spike at zero: a modified FP procedure and conceptual issues. Biometrical Journal 54 (5), 686–700.

Sauerbrei, W., Royston P. (2011): A new strategy for meta-analysis of continuous covariates in observational studies. Statistics in Medicine 30 (28), 3341–3360.

Sauerbrei W., Boulesteix A.-L., Binder H. (2011): Stability investigations of multivariable regression models derived for low and high dimensional data. Journal of Biopharmaceutical Statistics, 21:1206-1231.

Boulesteix A.-L., Guillemot V., Sauerbrei W. (2011): Use of pretransformation to cope with extreme values in important candidate features. Biometrical Journal, 53(4): 673–688.

Buchholz A., Sauerbrei W. (2011): Comparison of procedures to assess non-linear and time- varying effects in multivariable models for survival data. Biometrical Journal, 53(2): 308–331.

Boulesteix A.-L., Sauerbrei W. (2011): Added predictive value of high-throughput molecular data to clinical data, and its validation. Briefings in Bioinformatics, 12(3): 215-229.

Mallett S., Timmer A., Sauerbrei W., Altman D.G. (2010): Reporting of prognostic studies of tumor markers: a review of published articles in relation to REMARK guidelines. British Journal of Cancer, 102:173-180.

Binder H., Sauerbrei W. (2010): Adding local components to global functions for continuous covariates in multivariable regression modeling. Statistics in Medicine, 29: 800-817.

Riley, R. D.,Sauerbrei, W., Altman, D.G. (2009): Prognostic markers in cancer: the evolution of evidence from single studies to meta-analysis, and beyond. British Journal of Cancer, 100:1219-1229.

Sauerbrei, W., Royston, P., Binder H (2007): Selection of important variables and determination of functional form for continuous predictors in multivariable model building. Statistics in Medicine, 26: 5512-5528.

Sauerbrei, W., Royston, P. (2007): Modelling to extract more information from clinical trials data - on some roles for the bootstrap. Statistics in Medicine, 26:4989-5001.

Sauerbrei, W., Royston, P., Look, M. (2007): A new proposal for multivariable modelling of time-varying effects in survival data based on fractional polynomial time-transformation.Biometrical Journal, 49: 453-473.

Royston, P., Altman, D.G., Sauerbrei, W. (2006): Dichotomizing continuous predictors in multiple regression: a bad idea. Statistics in Medicine, 25: 127-141.

Royston, P., Sauerbrei, W. (2004): A new approach to modelling interactions between treatment and continuous covariates in clinical trials by using fractional polynomials. Statistics in Medicine, 23:2509-2525.

Royston, P., Sauerbrei, W. (2004): ‘A new measure of prognostic separation in survival data.’ Statistics in Medicine, 23: 723-748

Sauerbrei, W., Royston, P. (1999): ‘Building multivariable prognostic and diagnostic models : Transformation of the predictors by using fractional polynomials’. Journal of the Royal Statistical Society, A. 162:71-94; Corrigendum (2002), 165: 339-400

Sauerbrei, W. (1999): ‘The use of resampling methods to simplify regression models in medical statistics’, Applied Statistics,48:313-329.70.

Graf, E., Schmoor, C., Sauerbrei, W., Schumacher, M. (1999): ‘Assessment and comparison of prognostic classification schemes for survival data’, Statistics in Medicine, 18:2529-2545.

Blettner, M., Sauerbrei, W., Schlehofer, B., Scheuchenpflug, T., Friedenreich, C. (1999): ‘Traditional reviews, meta-analyses and pooled analyses in epidemiology’, International Journal of Epidemiology, 28:1-9.

Sauerbrei, W., Schumacher, M. (1992): ‘A Bootstrap Resampling Procedure for Model Building: Application to the Cox Regression Model’, Statistics in Medicine, 11: 2093-2109.


University of Freiburg Research Database:

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Short CV

2002 Habilitation in Medical Biometry
  Medical Faculty, University of Freiburg
1992 Dr.rer.nat.
  Department of Statistics, University of Dortmund
1986-2002 Head of the Methodical Centre
  IMBI, University Hospital Freiburg
Since 1986 Assistant professor
  IMBI, University Hospital Freiburg
1983-1986 Scientific collaborator
  Institute for Medical Statistics and Documentation, University of Erlangen
1983 Diploma in Statistics
  University of Dortmund





Statistical model building and evaluation of influence factors in clinical and epidemiological studies
(only in German, but based on publications in English)

Habilitation can be downloaded here.

In this paper I have tried to summarize for methodologically-interested clinicians my methodical works and their meaning for research in clinical epidemiology. At particular interest one has to read the cited original publications. Statisticians will find a detailed discussion on many issues in Schumacher M, Holländer N, Schwarzer G, Binder H and Sauerbrei W (2012)





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