The variation of performance explained by students' socio-economic status is higher (16%) than the OECD average (13%). Rurality is an important aspect of disadvantage in Costa Rica. Students in rural schools are more likely to drop out and fall behind in their learning than those in urban ones, with small rural primary' schools demonstrating the lowest performance rates in the country (PEN, 2013). The large number of small primary schools has enabled Costa Rica to bring education services to every small village.