I showed this discussion to my D who is a senior majoring in economics at Pomona. She’s also planning on going to grad school to get a PhD after working for a couple years. Her take: if you want to do economics research as an undergrad, go somewhere where they’re doing some research but, most importantly, where the professors are accessible to undergrads.
She pointed out that most econ undergrads are not even trying to do research. It’s a very popular major among students who have no intention of getting a PhD in economics, but rather want to go into business/banking/finance/law or any number of other career paths. For example, in D’s senior class at Pomona there are probably 50-60 econ majors and she estimates that only about 5-8 of those (including her) were trying to do research and all those who wanted opportunities had them.
D has been published as a co-author with one of her professors in an academic journal and has presented a paper at a conference where she was the only undergraduate presenter. She will be an RA at one of the Federal Reserve Banks after graduation. (She wanted to work for a couple years before applying to grad school.) When she was interviewing for jobs she got positive feedback (from one of the senior economists at the FRB) that she had significantly more research experience than the other applicants. As @Coloradomama mentioned, she’s followed the advice to take lots of math (linear algebra, real analysis, differential equations, probability, computational statistics, game theory).