The PhD is the primary research degree that can be taken in the Computer Laboratory. The Cambridge PhD is a three-year programme of individual research on a topic agreed by the student and the Laboratory, under the guidance of a staff member as the student's supervisor. All research students are admitted to read for the PhD Degree on a probationary basis and most will be registered for the Certificate of Postgraduate Study (CPGS) in the first instance. During this year students may do some additional coursework and will write a research report that is likely to form the foundation of the eventual PhD dissertation. The CPGS will involve four components: Research Skills training; Practical work; Research report of no more than 10,000 words and Attendance at a research workshops and research seminars. At the end of the third term and on completion of the CPGS, students whose performance indicates that they would be able to complete a PhD in reasonable time will be upgraded to PhD status. A student who is not upgraded to PhD status will normally be awarded the CPGS (as will a student who is upgraded to PhD status) but will leave before submitting a PhD dissertation. Students are expected to complete the substance of their research by the end of their third year, submitting their thesis then or within a few months.