The book �Smart Boys� by Barbara A. Kerr, Ph.D. and Sanford J. Cohn, Ph.D. has a short section that addresses causes of �overachievement� which they define as when a child�s academic performance is higher than that predicted by psychological tests.

The two main categories are;

1. The Student has test Anxiety (Self explanatory)

2. The Student is Benefiting from a Reputation or Halo Effect
This could be caused by older siblings, family reputation or high interpersonal skills.