Job Creation or Destruction? Labor Market Effects of Wal-Mart Expansion
用工具变量法估计沃尔玛进入对美国县级零售业就业的影响，发现进入当年增加100个岗位，但五年后净增仅50个，同时批发业就业减少约20个，且无显著溢出效应。
Abstract—This paper estimates the effect of Wal-Mart expansion on retail employment at the county level. Using an instrumental variables approach to correct for both measurement error in entry dates and endogeneity of the timing of entry, I find that Wal-Mart entry increases retail employment by 100 jobs in the year of entry. Half of this gain disappears over the next five years as other retail establishments exit and contract, leaving a long-run statistically significant net gain of 50 jobs. Wholesale employ-ment declines by approximately 20 jobs due to Wal-Mart’s vertical integration. No spillover effect is detected in retail sectors in which Wal-Mart does not compete directly, suggesting Wal-Mart does not create agglomeration economies in retail trade at the county level. I.