 A study done by Dissertation Genius1 reports that attrition rates are very high.
The rates range anywhere from one-third to one-half of those enrolled in a
doctoral program will not complete the program. They also report that those
rates have been fairly stable over the past three decades.
 A study done by Happy PhD2 reports even higher completion rates of 40%-60%
do not complete their program.
 A study done by The Council of Graduate Schools3 looked at 49,000 students
attending 30 institutions in 54 disciplines comprising of 330 programs reports
that the ten- year completion rate after students begin their doctoral program
remained at 56%. Which means 43.4% of students will not complete their
program.
These studies are just a few of many that support the same findings of dismal
doctoral program completion rates.