- Theories that conclude that advantaged peers is beneficial for disadvantaged students include: epidemic, cognitive, institutional-resources, institutional-expectations, disruption theories.
- Theories that conclude that advantaged peers are harmful for achievement of disadvantaged students include: relative deprivation, oppositional culture, signaling, focus-boutique.
- Theories that conclude that peers have no influence in the achievement of disadvantaged peers include: home influences and tracking.
- All economic theories view peers as instrumental to individual well-being, whereas other theories (from sociology, anthropology, political science, psychology) hypothesize that peers influence the beliefs and values of individuals.
- Despite using data in different states and somewhat different value-added approaches, there were at least three consistent findings across studies (value-added studies that use quasi-experimental methods to address nonrandom selection): (1) Having more advantaged peers generally results in better outcomes for minority students. (2) The benefits of advantaged peers for Whites are smaller than the benefits for minorities. (3) The value added studies suggest that each racial group appears to be influenced most by peers of their own race.
- Peer influences are race dependent and complex.
- Author proposes a new theory that peer effects are driven partly by group-based contagion in which students follow the leads of their classmates – especially those classmates who belong to the same group.
- Collectively, the theory and evidence point toward a new theory- group-based contagion- in which students benefit from advantaged peers mainly when those peers are in the same group. In addition, there is clear evidence that peers indirectly influence one another by affecting the school resources to which they have access, especially the qualifications of the teachers who teach them.