possibletransfer?

Thanks for the advice @cyberwulf! I will be sure to keep it in mind if I end up trying to transfer. I guess my other question is, if I do apply to transfer, and either I get rejected from all the programs I apply to or I decide that I actually wish to stay in my current program, would there be any tension between me and the faculty at my current program? I'm trying to do it as graciously as possible, but I'm afraid that some of the people in my program (my adviser in particular, who is funding me with his grant) might take offense if I try to leave.

@marmle I haven't really talked to anyone in my department about this because I don't want them to know that I'm thinking about transferring until I'm sure that I am going to. As for your other points, I'm thinking about transferring because I want to take more theoretical and upper-level math classes, which the department won't accept for the degree requirements even after petitioning. While I enjoyed my first year at my program, I don't think I'm a good fit with its goals and focuses, and I'd really like to make the switch to statistics or something more math-oriented.

Does anyone have any experience with transferring from a Biostatistics to a Statistics PhD program? I finished my first year at a top 3 Biostat PhD program earlier this year (i.e. one of Harvard, Johns Hopkins, or Washington), and I'm finding out that while I really enjoyed the statistics that I've learned, I don't want to be limited to biostatistical applications/methodology for the rest of my career. In particular, I want to focus more on theory and other topics more common in a Statistics program (such as ML, high dim data, etc.), which will hopefully make me more marketable for a wider range of companies/industries that may not be biologically-oriented. If I really wanted to transfer, I would need to apply this year (i.e. during my second year into my program before I get my Masters degree), since I think waiting for my third year would be too late, as I would then already be a PhD candidate at my current institution. I know that many people have said that programs aren't really a fan of you leaving a doctoral program for another one, since they've already given you year(s) of funding just for you to leave them, so that's what I'm mainly worried about. I did pretty well during my first year of my program (almost a 4.0 GPA, some research done with a established professor, one publication), but I'm wary of asking current professors for a letter of recommendation, since they might not appreciate my trying to leave the program. Has anyone gone through the process of transferring to a different program, and how did you navigate this process? Will other universities not look kindly on my trying to switch into a Statistics PhD program? What programs should I aim for if I do decide to transfer (for instance, would it be feasible to apply for the Statistics PhD program at my own university)? For more context, my undergrad GPA was between 3.7 and 3.8 from a non-HYP Ivy, and I think my GRE scores won't be a problem either, except that I haven't taken the Math GRE subject test.