Recommendation letter from advisor with different research interest

Question

While I was an undergrad, I wrote a paper on topic A with my advisor. Currently, I'm working in a research institution with an Economist whose work mainly lies on topic B. However, I've come to understand that I do not like A or B, but I'm more interested in topic C, and I've done some independent study on topic C. I'm thinking of asking my undergrad advisor and my current Economist for recommendation letter to apply for PhD in topic C.

How will admission committee for PhD view such recommendation letters from academics whose work is not on my current interest? That is, will it have any negative influence in my application, if I seemed to change my interest often?

To be specific, all topic A, B and C is under the field of Economics, but are vastly different from one another (especially the switch from A to B; it was like learning completely new subject). Knowledge gained from A and B can only be partially transferred to C.

Related, but does not quite answer the question that I have: Value of recommendation letters from professors in a different field. My question is more focused on the fact that two recommendation letters will show my interest in certain research topics were very short-lived.

Answer 1

I do not think it matters. If these people can best speak to your abilities then that's that. The key point should be to get letters of reference from people who can give context to your application and your achievements beyond the information the committee will get from your transcripts and other documents you submitted with your file.

Knowledge between fields may not be completely transferable, but research skills often are. Thus, a recommendation like "This guy is great because he got an A in my class on topic C" is useless, but someone who can expand on your ability to find resources and data, to analyze this data, even on topic A or B, is much more valuable.

The committee may regard your change of interest as positive or negative - this depends on committee I suppose, although I don't know of very many places where the expectation is that your interests as an undergraduate and junior graduate students will not change, especially as research topics are often driven by those of the supervisor.

Answer 2

It is quite understandable for an undergrad to still be exploring interests. In your application, it is good to create a narrative that links together A,B & C so that a reader can see your thought process and see that you were adapting your interests as you learned more rather than just getting bored and moving on to something new. I agree with @user67075 that the letters speak more to your aptitude/character than specific interests.

Answer 3

I think it depends on exactly how long you worked with these two individuals and what you accomplished. You want strong letters, so if you worked with both of them long enough for them to assess your basic research abilities and potential to develop into an independent researcher, I think the fact that they don't work in your exact desired field won't matter much. The fact that all three topics fall under the same Economics umbrella probably makes it even less of an issue.

It is true that sustained interest in a field/topic is usually a positive. However, I think you and your recommendation letters can spin even short-lived interests into a positive thing if you demonstrate that your prior experiences in A and B were valuable from a research skills development standpoint, while also helping you narrow your research interests down to topic C. Switching topics after you start a PhD can become difficult (especially the longer you wait), so admissions committees may look favorably on any prior work that helps you discover your research passion.