At the same time, class sizes are small, although OECD evidence suggests that class size is a far less important factor than teacher qualifications for student’s learning progress. Increasing class sizes may be one way to free the resources needed for providing extra teaching time to those at risk of dropping out of the school system. Socio-economic status is measured by the PISA index of economic, social and cultural status. Enrolment in adult education programmes has risen sharply as of the school year 2008-09, although most of the sharp increase was accounted for by the national scheme of recognition, validation and skills certification (RVCC).