The four contributions included in this special issue on effects of private tutoring illuminate different facets of this phenomenon. To join and integrate these different research approaches about private tutoring, Bronfenbrenner’s ecological systems theory (Bronfenbrenner, 1994) will be applied. Bronfenbrenner’s theory is well suited for this purpose as it allows reconstructing the different ecological systems relevant to private tutoring as well as the relations between these systems. The application of Bronfenbrenner’s terminology reveals, which systems and relations deserve greater consideration in further research.

Keywords
Private tutoring; Ecological systems theory; Microsystem; Mesosystem; Macrosystem