| PhD | Assistant professor | Associate professor | Full professor |
R square | 0.48 | 0.62 | 0.636 | 0.594 |
F | 25,751 | 40,757 | 43,617 | 36,624 |
p-value | 0.000a | 0.000a | 0.000a | 0.000a |
β | 1892 | 1754 | 1923 | 1817 |
T | 5075 | 6384 | 6604 | 6052 |
p-value | 0.000a | 0.000a | 0.000a | 0.000a |