In the years between the completion of his dissertation and habilitation, Weber took an interest in contemporary social policy. In 1888, he joined the Verein für Socialpolitik,[39] a new professional association of German economists affiliated with the historical school, who saw the role of economics primarily as finding solutions to the social problems of the age and who pioneered large scale statistical studies of economic issues. He also involved himself in politics, joining the left-leaning Evangelical Social Congress.[40] In 1890, the Verein established a research program to examine "the Polish question", or ostflucht: the influx of Polish farm workers into eastern Germany as local labourers migrated to Germany's rapidly industrialising cities.[3] Weber was put in charge of the study and wrote a large part of the final report,[3][39] which generated considerable attention and controversy, marking the beginning of Weber's renown as a social scientist.[3]