Is it possible for a university professor to truly change fields while staying an academic in the same university? For instance from computational statistics to data science, operations research, computational finance or dynamical systems?
How about publishing in a new field where no one knows you? I find it challenging (as a non-academic research scientist) but feasible. I don't publish in academic journals, so this is not an issue for me. And maybe the fields of interest are dictated by politics in Academia (the availability of grants, and what your department decides) making it more challenging. Any experience that you would like to share, about moving to a truly new field (many professors in statistics re-labeled themselves as data scientists, but still doing the same research, so it is not really a change of field.)
Share your story here, with the challenges and rewards.
A tenured full professor can work in any field that they wish! That's really the whole point of tenure: i.e., it provides academic freedom to pursue any line of research. Furthermore, Full Professor is the highest rank for university faculty (not including administrative advancements to Dean or Provost, or endowed Professorships), so there is essentially no impact on career advancement for someone to work on research topics that have nothing to do with the original research focus area in which the university hired that person. That scenario actually reflects my own path at the university: I was hired as Professor of Astrophysics and Computational Science, but I never taught an astrophysics course there (even though my PhD and my 20-year career prior to being hired were all in astrophysics), but instead I focused almost exclusively on data science and/or computational data science (in my research, teaching, and advising). With tenure, I had the freedom to do that. Conversely, a junior non-tenured faculty member may be denied tenure if they do this, since the first-level tenure review is typically conducted by your peers in your department --- so, if you are not providing the benefits in the research domain for which they hired you, then they could recommend against your tenure advancement, and thus your future in that department may be non-existent.
Regarding publishing, that's a different challenge. Publishing in any field in which you have no track record is hard, both for young and for established researchers. It can be done, but it is difficult. Note that second-tier journals would normally accept such papers that top-tier journals would not accept. But, again, for a tenured full professor, it is not nearly as important to publish in top journals as it is for the junior faculty member who does not yet have tenure --- that person's academic future depends on frequent peer-reviewed research papers in highly rated (i.e., highly cited) publications.
All of the above comments equally apply to grants. I had greater than 50% success rate for nearly 20 years in my grant proposals that were strictly related to astrophysics research. I was considered highly successful in my field in proposal-writing. But, as soon as I started submitting proposals related to data science, machine learning, data mining, etc., suddenly my ability to write a good proposal magically evaporated (overnight!), or at least that's the excuse that the funding agencies gave me when I questioned why my proposals were no longer being funded! There was definitely bias on the proposal review committees (comprised of peer researchers) against newcomers to their field! I saw it all of the time when I sat on those types of proposal review panels, which was quite frequent and frustrating! Of course, it didn't help that funding for research was dwindling over the years, and consequently the success rate for funding proposals dropped from about 1 in 3 to approximately 1 in 10 (or worse!).
For me, in the end, the reward was in doing what I loved the most. That's the important thing in life anyway: doing what pleases you, not trying to please other people!
Thank you Kirk for your very insightful answer!