¬¬A COMPETING EVENTS SURVIVAL ANALYSIS OF ATTRITION AND RETENTION AT FIVE SCIENCE AND ENGINEERING DOCTORAL PROGRAMS AT A RESEARCH UNIVERSITY

Abstract

There is continued concern about enrolling adequate numbers of students in science and engineering doctoral programs in the U.S., which is underscored by studies that find graduation rates of only 40% to 60%. The situation is especially acute for women and underrepresented groups who enroll and graduate at disproportionately low rates. This study uses a competing events survival method to assess the probability of graduating or withdrawing using a sample of 1,358 students in five science and engineering doctoral programs in a research university. Continuous time in days is used to track student progress over eighteen years to completion of their dissertation defense or to withdrawal. Kaplan-Meier survival estimates and life tables were generated. Students are most likely to withdraw during Tinto’s transition and skills-acquisition stages. Results show that the risk of withdrawing is greatest in the first three years when nearly 80% of those who withdraw have done so. The probability of graduating is highest for students who had a funding package of mostly research assistantships or an even mix of research assistantships, teaching assistantships, and fellowships. Those who score high on the GRE Analytical Writing test, which is rarely studied, are more likely to graduate than those with lower scores. Time to degree is shortest for students who had a funding package of mixed TAs/Fellowships, TAs/RAs, or mostly TAs. While there is a significant association between a lower graduation rate and having mostly TA funding, the association likely occurs because students have more TAs in their first years and most withdrawals occur in the first three years. The probability of graduating is lower for underrepresented students than for whites and slightly lower women than men. International students graduate at the same rate as U.S students. With the exception of men students with men advisors in Mechanical Engineering, the sex of a student’s advisor has no significant correlation with the graduation rates of men and women students.