When I'm involved in a project with the goal of analyzing (following some previously stated criteria) a set of research papers, which word is more suitable: inquiry or investigation? Or neither? If neither, please let me know what your suggestion is.
Are you assessing these papers for the purpose of assigning a "grade"? In that case, you are involved in analyzing their inquiries for the purpose of assessment. If you are analyzing these research papers, then you are figuring out distinctive features of each such as validity, reliability, and writing or argument strength. If you are "investigating" these research papers, it sounds more like checking into the originality of each to me.