While some progress has been made in understanding the relationships between earnings dynamics and the job mobility of workers, a complete analysis has been hampered by the lack of a framework to distinguish the relative importance of various theories of mobility. The purpose of this research is to develop and carry out an extensive set of tests of competing theories of mobility using information primarily on (1) the pattern of prior mobility, (2) wage and mobility histories following involuntary job changes, (3) mobility during the first year on the job, and (4) the relationship between the method of job search and mobility. Longitudinal data from a varied of sources, starting with the NLS youth cohort, will be used to implement the model. In addition, to distinguishing the various theories, important facts will be learned about labor market dynamics and specific patterns of mobility. This project is important because it will increase our understanding of job mobility which will begin to help us explain the patterns of wage growth within and between jobs.