I want to apply to PhD programs in Biostatistics, but I've been hearing that I should already have well-developed thesis ideas. I don't. There are areas of statistics that I'd like to learn more about, but I can't say that I have a specific thesis idea. I feel I have a lot more learning to do before I could have an intelligent thesis topic. I have an MS in Statistics, but there was no masters' thesis, so I didn't really gain "expertise" in any particular topic.
I've also been hearing that I should email potential advisors and tell them about my ideas, which freaks me out since I don't have a thesis idea! It seems like a terrible catch-22. How can I become savvy enough to have a viable thesis idea unless I get to take PhD-level classes? And how can I get to take PhD-level classes if I can't get into a program until I have a thesis topic?
Other than this (major) problem, I think I'm a good candidate – very high GPA and GRE scores, brand-name education, first-author publications, work experience, great references. But at this point I'm starting to feel thoroughly overwhelmed by the prospect of coming up with a thesis topic.
I'd really appreciate any advice. Thanks.