How long does it take to get a PhD in the U.S.?

The National Science Foundation has data on that

When I defended my dissertation and completed my biochemistry PhD in 2011 at Arizona State University, it had been about 5 years since I arrived in Tempe, Arizona with my belongings stuffed into my Ford Escort. In the lab group I was part of, 5 years was a pretty normal amount of time to finish your PhD as long as you met the department’s minimum requirements and the unwritten requirement of publishing at least one paper. The possibility of a 4-year PhD was even rumored within the department, but I never knew anyone to give credence to that legend.

I probably could have benefitted from an additional year in graduate school to push my project further before looking for a postdoc position. Doing so would have put me closer to the average amount of time it takes to complete a biochemistry PhD. We have data on this because the National Science Foundation (NSF) surveys how long it takes for a PhD in many different fields every 5 years since 1972. In fact, this NSF Survey of Earned Doctorates has all kinds of interesting data about graduate school, parsed by demographics, fields and subfields, geography, and more.

Anyway, here’s a data visualization I made showing what the time to complete a PhD looks like like over time and by general field.

For reasons I’m unsure of, there was a peak around 1992 across all fields, and the time has crept downward and mostly stabilized since then. This is really prominent in education, where getting a PhD takes the longest (and is different than and EdD, which is more practice-oriented rather than research-oriented).

Also, this data is measured from the time people begin graduate school, which can mean those who do a master’s program and then a doctorate program, as well as those who just do a doctorate program. So, I think those doing both a master’s and a doctorate might be inflating the numbers a bit.

Here are the subfields that fall under each of the 8 general categories I included in the graph above:

Life Sciences: Agricultural sciences and natural resources, Biological and biomedical sciences, Health sciences

Physical & Earth Sciences: Chemistry, Geosciences, Physics and astronomy

Mathematics & Computer Science: Computer and information sciences, Mathematics and statistics

Psychology & Social Sciences: Psychology, Anthropology, Economics, Political science, Sociology, Other social sciences

Engineering: Aerospace, aeronautical, and astronautical engineering, Bioengineering and biomedical engineering, Chemical engineering, Civil engineering, Electrical, electronics, and communications engineering, Industrial and manufacturing engineering, Materials science engineering, Mechanical engineering, Other engineering

Education: Education administration, Education research, Teacher education, Teaching fields, Other education

Humanities & Arts: Foreign languages and literature, History, Letters, Other humanities and arts

Other: Business management and administration, Communication, Non-science and engineering fields

Robert Lawrence writes about science and illustrates data. You can find his published work at www.robertlawrencephd.com