What is the difference between self-concept and self-esteem in school-age children?

In middle childhood, children's emerging cognitive capacities enable them to think about themselves in new, more complex ways and develop more sophisticated and comprehensive self-concepts. Self-concept shifts from concrete descriptions of behavior to trait-like psychological constructs (e.g., popular, smart, good looking. For example, consider this school-age child's self-description: "I'm pretty popular … because I'm nice to people and helpful and can keep secrets. Mostly I am nice to my friends, although if I get in a bad mood I sometimes say something that can be a little mean". Like most older children, this child's self-concept focuses on competencies and personality traits rather than specific behaviors. Whereas preschoolers tend to have unrealistically positive self-evaluations, school-age children's sense of self-esteem becomes more realistic. Older children's growing ability to take other people's perspectives enables them to consider their abilities more objectively. Children evaluate their characteristics, abilities, and performance in comparison with peers, which influences their overall sense of competence. Children also receive feedback about their abilities from parents, teachers, and peers, and this affects their self-esteem