In 1984 he worked as a guest professor at the Department of Biostatistics of the University of Washington in Seattle, WA (USA).

He was a member of the Faculty of Mathematics and Physics and there has been a cooperation with researchers and scientists in the fields of mathematics, physics, biology and computer science within the framework of the interdisciplinary Freiburg Center for Data Analysis and Modeling (FDM).

There were several international symposia focused on methodology, Martin Schumacher also recurrently hosted conferences on medical statistics in Oberwolfach and the International Biometrical Conference (IBC) in 2002, as well as the third meeting of the German Consortium in Statistics (DAGStat 2013).

His international reputation can also be gleaned by the fact that he got invited to give the 21st Bradford Hill Memorial Lecture in 2012.

He published many papers about various methodological and statistical aspects of the planning and analysis of studies in the field of clinical epidemiology.