Why are residential and school moves associated with poor school performance?

Most research on residential mobility has documented a clear pattern: Residential and school moves are associated with poor academic performance. Explanations for this relationship, however remain speculative. Some researchers argue that moving affects so- cial relationships that are important to academic achievement. But the association between moving and school performance may be spurious: the negative correlation may be a function of other characteristics of people who move often. We offer several conceptual and analytical refinements to these ideas, allowing us to produce more precise tests than past researchers. Using longitudinal data, we find that differences in achievement between movers and nonmovers are partially a result of declines in social relationships experienced by students who move. Most of the negative effect of moving, however, is dice to preexisting differences between the two groups.