Result of linear regression of the student’s academic progress over one year (y) on four independent variables measured in January 2011.

y = −14.124 + 0.204g + 0.127xacquaintance + 0.230xfriend + 0.147xbest friendIndependent variables are: g: student’s academic ranking, and xi: difference in ranking between each student’s self-reported neighbors’ average GPA and his/her own GPA, where i is either acquaintance, friend or best friend. A highly significant effect of g was due to the fact that top-ranked students did not change their academic rankings much after one year.