Attendance is almost universal at these two levels, which contrasts with low attendance rates in pre-primary education. The size and location of schools are key distinctive features of the Kazakh school network. Urban schools tend to suffer from a shortage of student places and operate in multiple shifts. In contrast, low density of population and a policy that favours universal access have resulted in a large number of small-class schools (about 50% of all schools). Student learning outcomes, as measured by PISA, are considerably below the OECD average. The difference in the mean performance in mathematics suggests that Kazakh 25-year-olds are on average two years behind their peers in OECD countries.