This is from a working paper by Richard Hanania of Columbia University and Max Abrahms of Northeastern University:
We argue that experts are more hawkish the closer they are to power, both figuratively and literally, and show this through the first study to use survey methods to inquire into the foreign policy preferences of think tank analysts and fellows (think tank employees, or TTEs) relative to professors who are experts in international relations. We find that TTEs are 0.47 standard deviations more hawkish than professors as calculated based on a standard survey measuring militant internationalism (MI). Controlling for self-described ideology mitigates this effect although it remains statistically significant. Among professors, those who have worked for the federal government are higher on MI, as are TTEs located closer to Capitol Hill. Differing levels of regional expertise generally cannot explain these differences, except perhaps in the case of Iran.
The full report can be found here.