A Practical Guide to Shift-Share Instruments
梳理了Shift-Share工具变量识别的两条路径（利用外生冲击或外生份额），通过简单清单给出实用建议，并用多个实证案例说明要点。
A recent econometric literature shows two distinct paths for identification with shift-share instruments, leveraging either many exogenous shifts or exogenous shares. We present the core logic of both paths and practical takeaways via simple checklists. A variety of empirical settings illustrate key points.