In academia, after a reasonable probationary period of service and upon the achievement of tenure, the recipients of tenure are entitled to a continuing appointment at an institution without mandatory retirement and with only limited grounds for revocation. Advocates of tenure argued that it protected academic freedom through economic security. Opponents of tenure argued that it fostered inefficient and unproductive behavior. This dissertation developed a framework for examining academic tenure in U.S. economics departments. I constructed a dataset of tenured U.S. economics professors who were Ph.D. recipients between 1990 and 2006 and tracked their publications. In the first chapter, based on difference-in-difference analysis I found that tenure has a direct effect on the choice of research direction/focus. In general, tenured groups had a higher degree of specialization than non-tenured groups after they received tenure. For some tenured groups, even if their extent of specialization decreased after tenure, when I controlled for unobserved heterogeneity, tenure still had a positive effect on extent of specialization. This result suggested that the job security provided by tenure made tenured faculty more narrowly focused on their research. Using path analysis in the second chapter, my finding suggested that the extent of specialization was one of the key factors which might influence a scholar’s productivity. In addition, the extent of specialization helped explain gender differences in academic productivity. The results revealed that the effect of gender on productivity through the degree of specialization was more notable among older generations, and in most fields, gender differences in extent of research specialization mediated gender difference in research performance; although there were some fields in which gender difference in the research process could not explain gender difference in research performance. The third chapter expanded our understanding of advancement in academics by exploring a new dimension of inquiry: whether the extent of specialization in scholars’ research programs improved promotion prospects. Using discrete event analysis, my research showed that the extent of research specialization contributed to career acceleration, although gender difference on the prospects of advancement in academics was not significant.