In the 1960s and 70s in America, psychologists identified low student self-esteem as a real problem, and there’s no doubt they were right about that; self-esteem was a problem. They tried to address it by building up self-esteem by not criticising students. So they would say to students 'this is great' when the work they had done was, actually, pretty bad. The problem with that approach is that it is possible to build up self-esteem on a short-term basis, but the bubble gets very easily pricked… and if all you’ve done is build self-esteem, when students get disconfirming evidence; when students find out that they're not as great as they thought they were, there is nothing to fall back on. And what you get is a much more profound collapse, so they are actually in a much worse state than if you had never done it.
A much more important concept is that of self-efficacy. Now, the difference is that self-esteem is feeling good about yourself; self-efficacy is feeling good about yourself because of what you can do. And what the work of Albert Bandura, and others, has shown is that when you focus on self-efficacy, when you get students to feel good about themselves because they know they can learn; because they know they can improve; because of what they have accomplished… then that is much more stable, it's robust, and it feeds forward into students’ future activities.
So, building self-esteem for self-esteem’s sake is short-sighted and, ultimately, counter-productive. But if we can focus on self-efficacy by feeding into children that everything they do can feed into where they can be, then the effects, over the whole life course, are very positive.