This is particularly important for students from disadvantaged backgrounds, for whom school may be their main means to develop skills. Reaching close to the OECD average number of years of education appears to provide a protective factor for students in improving the likelihood of academic success. This largely arises because to reach the OECD average of 14 years, students need to enter the education system at age 3 or 4 and remain in it until age 17 or 18. Early skill development starts primarily in the home, building on early attachment, with activities between children and their parents and/or caregivers being the main determinant of early learning.