The Ph.D. degree is intended for students planning to pursue a career in computer science research and education. The doctoral program normally requires four to six years of study. Ph.D. students must spend at least four semesters in full-time study at Rice, where full-time study is defined as enrollment in nine or more hours of coursework. The Ph.D. degree requires a combination of coursework and original research, as evidenced in a written thesis and a public oral defense of that thesis.