How does the profession of economics as a science work nowadays? How is new research added to the wealth of knowledge?
Well, researchers write “papers” and these are published in journals. There are more than 1000 journals (in economics) with probably more than 50 papers per year each, so at least 50.000 papers a year, clearly much more than any single person can read. There is a lot of specialization in economic research and there are also huge quality differences between papers and also between journals. Publishing is not easy. You write a paper and then you submit it to a journal. An editor looks at your paper and either rejects it outright or sends it on to referees (other researchers). These referees evaluate your paper along the following criteria: correctness (of facts and of the logic / math / stats used), originality (you cannot publish something that is not new), importance, plausibility, readability, and whether the paper changes our view of something. If any of these criteria are not met, the paper will typically be rejected. Of course referees also make mistakes (it is not easy, for instance, to judge the importance of things that have never been done before). Different journals have different standards and there is a relatively clear ranking of journals (still often debated). A simple ranking (only of better journals) that I like is given in this blog post, but there are other, conceptually perhaps even more appropriate, ranking methodologies. Of course there are bad papers in good journals and good papers in bad journals, but if I am interested in a certain topic I would usually start by looking up (using google scholar) what I can find on this topic in the top 5 journals (American Economic Review, Econometrica, Journal of Political Economy, Review of Economic Studies, Quarterly Journal of Economics) in recent years, or ideally recent survey papers in the Journal of Economic Perspective and the Journal of Economic Literature, and then I would start reading in zig-zag fashion from there: If you don’t understand something in this paper read the papers that are cited in this paper and that are supposed to explain these things better and then come back to the original paper. You may also want to read some of the papers that cite this paper (use google scholar for this). These papers will include things that you don’t understand, so read those papers that help you to understand these and then come back again.
In my opinion, What should you do if you want to become an economics researcher? You should study economics (mostly to see what questions economists have studied and how they have attempted to answer them). You should study mathematics, because this is the language of economic theory. You should study statistics (which requires mathematics), because this is the toolset for doing empirical research. You should learn how to write (academically) and how to give talks and presentations, because this is how science is communicated to other scientists and the rest of the world (and all this in English). All of this, you learn to some extent in the courses in economics, but in order to become a researcher, this is probably not sufficient. You should take up courses from the math and stats departments as well. Some of my colleagues even do improv theater (just to improve their science communication skills). Basically you want to have a large toolkit so that you can analyse any economics problem with the appropriate tools and not only with the tools you happen to know.
A final note, perhaps, and again very much only my opinion: the more brilliantly creative and intuitive you are the less you may need to know the tools. But then again who is brilliant? And I am probably wrong about this anyway.