The PhD program aims to train independent researchers in biostatistics applications and methodology. The program includes the Master's program courses, comprehensive analysis of a dataset and reporting of results equivalent to the MS thesis, and at least one additional semester of advanced courses in statistical theory and methods. Students in the PhD program are also required to take courses toward a minor in biomedical science, pass both written and oral examinations, and successfully complete a doctoral dissertation. The PhD in Biostatistics typically requires five to six semesters of coursework and additional semesters devoted to dissertation research. This is usually accomplished in four to five years of full-time study. The standard course sequence for PhD students consists of 3 units in theory, 7 units in statistical methods, 2 units toward a minor and 3 units of electives in advanced theory and methods. In addition, a minimum of three semesters of lab rotations (BSTA 699) are required. In general, students are expected to have completed all required courses by the end of their 3th year (or equivalent for those who enter with a Masters degree). In rare cases substitutions may be made. Such alternatives must be pre-approved by the chair of the Curriculum Committee, the Program Chair, GGEB Chair and the director of the course being waived, who is in the best position to evaluate whether the necessary skills are met by the substitution.