Health economics is a topic that spans multiple disciplines, from economics to public policy to business to the medical and scientific literature. It is also a topic that is highly scrutinized by law makers and the popular media. As a result your research will most likely take you beyond research in economics.
You will need to start early and be critical of the information that you find. Who is the author, what are their credentials, political leanings, who are they speaking on behalf? Cite accurately - attribute ideas not your own to those of the proper owner.