I am a third year Statistics PhD student. As I have become more involved in the field, I have realized it is not as good a fit for me as I originally thought. I excel in applied, collaborative work but fall behind my peers in theoretical work. It is not that I am incapable of understanding theory, in fact I can understand and digest fairly technical literature, I just do not find it interesting enough to devote the time and attention to be really good. This is unfortunate for me because the field of statistics prefers novel theory to interesting applications. That is not a slight on the field; I should have had the self awareness to know my own interests and limitations before committing to graduate school.
Despite this, I am quite happy in my program. I have a wonderful, supportive advisor, and I am in one of those rare departments where the faculty seem to genuinely care about the students. I have mentioned to my advisor that I prefer applied work and he has generally given me collaborative projects with epidemiologists. I do this work very well (I have an upcoming publication in a leading epidemiology journal) and enjoy it tremendously, but it is not viewed as prestigious by scholars in my field.
I am interested in an academic career. The way I see it, I can be a mediocre statistician or I can be an excellent statistically inclined epidemiologist. I prefer the later. I do not want to switch fields during my PhD primarily for two reasons: (1) I am pretty far into my PhD and do not want to start over. (2) The academic job market is horrible and a statistics PhD translates better to industry and government jobs than an epidemiology degree if I am unable to secure an academic position.
Is it possible to transition from (bio)statistics to epidemiology during a post doc and then be competitive for an academic job afterwards?
EDIT: Anecdotal experience of people switching fields is also appreciated.