Big-fish–little-pond effect
The big-fish–little-pond effect (BFLPE) is a frame of reference model introduced by Herbert W. Marsh and John W. Parker in 1984. According to the model, individuals compare their own self-concept with their peers and equally capable individuals have higher self-concepts when in a less capable group than in a more capable group.
Source: Wikipedia — Big-fish–little-pond effect (CC BY-SA 4.0)