The GEM Report team is much to be applauded for focusing on the roles of non-state actors in education in its 2021 edition – the consultation for which is still open. Among these actors are private tutors. They may be university students and others who work informally as private tutors, teachers in public schools who take additional roles as private tutors, and entrepreneurs who operate tutorial centres as stand-alone enterprises and chains.

Private supplementary tutoring is widely known as shadow education because much of it mimics mainstream schooling. Across the world, many millions of students receive some form of shadow education each day. The 2017/8 GEM Report estimated that the size of the market would surpass US$227 billion by 2022.

Globally, the Republic of Korea is best known for the scale of shadow education. In 2018, 82% of elementary-school students were receiving supplementary support alongside 70% of middle-school and 65% of general-high-school students. Most of this support was in institutions called hagwons, which resembled the juku for which Japan is famous. Counterpart institutions are also very common in Mainland China and Hong Kong.

But private supplementary tutoring is not just an East Asian phenomenon. It has also expanded remarkably in Europe, for example.  A 2020 update of a 2011 report for the European Commission showed that shadow education is increasingly visible, including in Scandinavian countries where it had previously been negligible. England and Wales, for example, had little tradition of private supplementary tutoring in the past, at least for regular students in state schools; but a 2019 survey of students aged 11-16 by the Sutton Trust found that 27% of respondents in the total sample had received private tutoring at some point in their careers, rising to 41% among respondents in London.

Statistics from Egypt and India show that supplementary tutoring is also evident in lower-income countries. An Egyptian national survey cited by Sieverding et al. (2019) indicated that 36% of primary, 53% of lower-secondary, and 84% of general-secondary students were receiving supplementary tutoring. And in India’s West Bengal State, 70% of rural students in Grades 1-5 and 77% of rural students in Grades 6-8 sampled by Pratham (2019) were receiving private supplementary tutoring. Proportions for urban students would likely have been even greater. Updated evidence for Africa will be presented in the 2021 GEM Report.

The format for such tutoring may be very varied. It can be provided one-to-one, in small groups, or in large lecture theatres. Increasingly, tutoring is delivered over the internet. Such tutoring can bridge rural-urban divides, but also raises questions about content, pedagogy and regulation.

The issues also include questions about the roles of mainstream teachers. Public school teachers who provide supplementary tutoring can increase their incomes and perhaps are more likely to stay in the profession. However, in under-regulated settings teachers may be tempted to short-change their mainstream teaching in order to force their students to come to private classes after school. This pattern raises issues of corruption. And even in settings where teachers do not themselves provide tutoring, schools commonly assume that the majority of students gain extra support, and then themselves fail to provide all the support that they should.

Private supplementary tutoring is also a financial burden for millions of families, and raises major issues about social inequalities. The 2017/8 GEM Report indicated that the richest families in Viet Nam spent 14 times more on private tutoring than the poorest; and in 2015, 35% of United Kingdom parents who did not pay for private tutoring cited cost.

Shadow education is a growing phenomenon, and it must be analysed anew in the 2021 GEM Report on non-state actors. The implications of shadow education must be more transparent in connection with the SDG4 goal of inclusive and equitable quality education for all.