1. econ里每一个人都很smart，很多人还很自大，所以PS最好stay with the facts, no more. Be precise.
2. 关于怎么写自己在RA和coauthored paper里的贡献：Self recommendations are a necessary evil in academia. But, one can minimize the distaste by treating them impersonally, i.e., with the same standards with which we write papers. It is also reassuring to your coauthors that you remember precisely who contributed what since the only guardian of intellectual property rights before publication is our memories.