Students who move between schools often have more social, psychological, and academic problems than their peers whose enrollment is stable. However, the negative effects may also be felt among classrooms and schools. To date, much of the student mobility research do not control for demographics or prior achievement, and utilized a sample size of one school or district. The current study examined a statewide database to determine which student variables predict mobile status. Analyses also investigated the relationship between mobility and academic achievement for mobile students, as well as classrooms and schools, while controlling for demographics and prior achievement. The logistic regression analyses using demographics, special education status, attendance, and prior achievement as predictors were able to correctly predict less than 1% of mobile students, indicating that key predictors of mobility were not captured in state databases. Results of the HLM analyses showed that the composite variable encompassing all types of moves, in district move, between years, within year, and promotional move variables was associated with poorer achievement. A negative association was also found for classrooms and schools containing students who moved within the school year, indicating that negative effects are felt among stable students attending classrooms and schools with mobile students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]