Table 31. Median years to doctorate, by broad field of study: Selected years, 1990–2015
Field of study and time to degree 
1990 
1995 
2000 
2005 
2010 
2015 
All fields 






Since bachelor's 
10.6 
10.9 
10.3 
9.9 
9.3 
8.7 
Since starting graduate school 
8.7 
8.7 
8.5 
8.2 
7.7 
7.3 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
5.7 
Life sciences^{b} 






Since bachelor's 
9.2 
9.5 
9.1 
8.7 
8.6 
8.2 
Since starting graduate school 
7.7 
7.7 
7.7 
7.1 
6.8 
6.7 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
5.7 
Physical sciences and earth sciences 






Since bachelor's 
7.5 
8.1 
7.6 
7.5 
7.3 
7.0 
Since starting graduate school 
6.7 
6.9 
6.7 
6.6 
6.5 
6.2 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
5.7 
Mathematics and computer sciences 






Since bachelor's 
8.3 
9.0 
8.7 
8.3 
8.0 
7.8 
Since starting graduate school 
7.2 
7.7 
7.2 
7.2 
7.0 
6.7 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
5.7 
Psychology and social sciences 






Since bachelor's 
10.8 
10.6 
9.9 
10.0 
9.5 
9.3 
Since starting graduate school 
8.9 
8.7 
7.9 
8.2 
7.7 
7.7 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
6.0 
Engineering 






Since bachelor's 
8.3 
9.2 
8.7 
8.3 
7.8 
7.3 
Since starting graduate school 
6.7 
7.3 
7.2 
7.3 
6.9 
6.7 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
5.2 
Education 






Since bachelor's 
18.0 
19.9 
19.4 
17.4 
16.2 
14.8 
Since starting graduate school 
14.7 
15.7 
14.2 
13.0 
12.5 
11.7 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
6.0 
Humanities and arts 






Since bachelor's 
12.3 
12.1 
11.6 
12.0 
11.6 
11.0 
Since starting graduate school 
10.7 
10.1 
9.7 
9.9 
9.5 
9.2 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
6.9 
Other^{c} 






Since bachelor's 
13.2 
13.2 
13.6 
13.0 
12.1 
11.2 
Since starting graduate school 
10.3 
10.3 
10.2 
10.3 
9.3 
8.9 
Since starting doctoral program^{a} 
na 
na 
na 
na 
na 
5.3 