I work with the Stanford GSB Research Fellows Program, which is a two-year predoc program. Fellows work on research with GSB faculty and are eligible to take classes. We posed this question to our former fellows and received the below response (with permission to share):
"I do not think I would be in an economics PhD program today without having completed the Research Fellows predoc program at Stanford GSB for two reasons: my academic background and access to professors conducting economics research at a research university.
First, I was not a typical economics phd applicant; I did not major in economics or math, but rather in Chinese and political science. My interest in economics developed towards the end of my undergraduate career, but at that point I was unable to change course, being a double major. As a result, I had not taken any economics or math classes. Clearly this creates an issue in the application process. Participating in the Stanford GSB program allowed me to fill these gaps in my transcript by taking math classes and graduate level economics classes.
Second, coming from a small liberal arts college, I was not exposed to graduate students or the rigorous/fast-paced environment of a research university. The Fellows Program gave me the opportunity to work with professors on economics and related projects, strengthening my empirical and coding skills. I was able to look at questions from an economics mindset (increasingly so as I took more economics classes), and begin to develop my own framework and questions. Additionally, I got to interact with other graduate students and gain a realistic understanding of the rigors involved in a PhD program at a top university.
Given the high barriers to entry into an economics PhD, the Research Fellows program afforded me the opportunity to apply and gain entry to an Economics PhD program."