School Effects on Children’s DevelopmentIn order to study school effects scientifically, researchers are required to do randomized controlled experimental studies, which is not possible in practice due to ehtical problems. Therefore, schools have to be studied in their natural settings. For instance, one could study the difference in outcomes between term-time and summer break. In addition, one can use sound research methodology with powerful statistical analysis to study the difference between effective and ineffective schools.The  question one should ask in measuring school effects is the outcome of the effects. Research has, by and large, looked at academic achievement like reading  or math abilities as outcomes. However one can also study other outcome variables such as classroom behaviour, attitudes towards learning, self esteem, attendance rate, continuation in education, employment, social functioning, etc.School Effects on Cognitive developmentSchool Effects on general intelligenceStudies have shown that every missed school year is associated with a loss of 0.25-6 IQ points. Cross- cultural studies have shown that there is a difference in IQ between children who attend schools and those who do not. Studies in both developing and developed countries have shown that schooling is associated with gains in cognitive development. Forced closure of schools as a result of war or political problems has been followed by IQ decrements of about 5 points and continued schooling later is associated with an IQ gain of 5-7 points.School effects on academic achievementStudies have shown that children regress in their academic attainment during summer holiday especially for the disadvantaged children. The evidence for school effects  for secondary level is that the differences between the best and the worst schools, after controlling  the intake variables, are in the order of 1 SD in their level of academic attainment.Classroom influences, like teaching and learning processes, quantity and quality of teaching, are more powerful in affecting academic outcomes than non-classroom factors such as school buildings, the number of books in the library, ie learning resources are not as important as teaching and learning processes.Mechanism of school effects on cognitive developmentThe mechanism is likely to be that there is an interaction of experiences and children’s self- concept. This will make children have good attitudes, self-esteem and desire to learn actively. Learning how to learn is as important as the contents of learning. When children have good attitudes, self-esteem, desire to learn, adaptive styles to teachers and parents, these qualities will enhance their level of cognitive development.	Pre-school education brings about chains of changes in that it may open up or close down opportunities. The effects do not result from direct cognitive gain but favorable attitudes; good self-esteem and adaptive leaning styles will increase children’s opportunities, leading to increasing cognitive development.2. School Effects on Self-Esteem 	Schooling experience greatly affects children’s self esteem. Children who start with success will have better self-esteem, which will lead to further success. They would have more inspiration and motivation to learn, more achievement-oriented behaviour. So the ranking of their performance, marks, behaviour, teachers’ expectation- these will affect self-esteem. Vulnerable and disadvantaged children will benefit from good schooling experience. This can improve their self-concept and happiness, which will act as protective factors for their future.3. School Effects on Emotional and Social Development	Schools are a context for children to develop emotionally and socially. In order to understand school effects on emotinal and social development, one has to consider:Individual vulnerabilitiesSchool climateLow achievers are shown to have more emotional and behavioural problems. They may not like the school , leading to association with troublesome company and wrongdoing. Studies have shown that children with hyperactivity or attention deficit are at risk for rejection by peers and teachers, leading to feeling of shame and dislike for the school. When they reach middle childhood, they will have a sense of failure and poor self-concept, eventually leading to withdrawal, avoidance, depression or other emotional problems.School climate has an effect on children’s behaviour such as on-task behaviour in the class, delinquency rate, psychiatric disorders and use of alcohol. Conflicts and disharmony in schools are associated with attention problems, aggression and oppositional behaviour in children.One of the main problems in schools is bullying and victimization. Studies have shown that ex-vitims are associated with low self-esteem and depression. Severe and corporal punishment by teachers is associated with the use of violence in children.