Probability of Completing a PhD

According to the US Census Bureau, approximately 4.7% of Americans aged 25 and older hold a doctoral degree (including PhD, MD, JD, and other professional doctorates). Research doctorates (PhDs) specifically are held by about 2% of the population. About 55,000 research doctorates are awarded each year in the United States.

The path to a PhD is long and uncertain. The median time to complete a research doctorate is about 5.8 years after starting the program, with significant variation by field: physical sciences average about 5.5 years, engineering 5.3 years, social sciences 7.0 years, and humanities 7.5 years. The overall PhD completion rate is estimated at 50-60%, meaning 40-50% of students who begin a doctoral program do not finish.

PhD holders generally earn more than those with master's degrees (about 20-25% more on average), though this varies dramatically by field. STEM PhDs tend to have much higher earnings potential than humanities PhDs. Student loan debt among PhD holders averages about $100,000 for those who borrow, though many STEM programs offer full funding through assistantships and fellowships.