The public and policy-makers have recently begun to focus increased attention on this issue, which has not always received the attention provided to children and youngsters who have actually dropped out of school or who are involved in marginal activities such as delinquency or substance abuse. However, it is presumed that failure to integrate into the school system, as well as underachievement and behavioral problems that inhibit learning, all contribute to dropping out. These problems begin at a much earlier age and are far more common than dropping out itself. As in many other areas, the extent of this problem is unknown. However, the relatively large number of children in special classes for weak students and the substantial proportion of children who continue their education in lower level alternative vocational frameworks (see Education section) indicate that there are many children for whom education should be improved. The proportion of students who are confronted with problems of underachievement and failure to integrate successfully into the educational system is higher in peripheral areas, disadvantaged neighborhoods and in the Arab sector. There is also growing evidence that these problems are more pronounced among some immigrant children and youth (see Immigrant children section). Though most attention has been given to underachievers and weaker students in high schools, there is now more interest in developing effective interventions for children at earlier ages.