Countervailing Powers: Labor Unions Against the Buyer Power of Walmart Supercenters
中文摘要
权力是社会学解释经济不平等的核心；然而，买方势力——即一个或少数几个占支配地位的雇主能够限制工人外部就业选择的市场条件——与工人权力相比所受关注甚少。我们研究沃尔玛超级购物中心的进入如何影响工会会员的规模与保护力度（工人权力的一个关键维度）；沃尔玛超级购物中心正是高买方势力雇主的典型代表。我们分析了：(1) 更强的工人权力是否会使沃尔玛超级购物中心打消进入当地劳动力市场的念头；(2) 成功进入之后，超级购物中心是否随之侵蚀当地工会会员规模；(3) 成功进入之后，工会是否能为收入下滑提供保护效应。我们利用受限访问的收入动态追踪调查（Panel Study of Income Dynamics）数据，基于沃尔玛超级购物中心开业在县—年层面的变异，采用堆叠双重差分估计。我们发现，即便在以沃尔玛的进入尝试为条件的情况下，沃尔玛超级购物中心也更不可能进入工会会员比例较高的当地劳动力市场。当沃尔玛超级购物中心确实开业时，工会会员比例平均下降3.5个百分点，且这一下降是通过零售业工会会员数量的减少而实现的。留存的工会会员并未免受沃尔玛对收入造成的下行压力；事实上，沃尔玛超级购物中心开业后，处理前已加入工会的工人的年收入比非工会会员下降得更快。工人权力能够有效阻止买方势力的上升，但一旦买方势力增加，工人权力在规模与保护力度两方面都趋于下降。对劳动力市场权力的社会学研究应当考虑，现存的买方势力水平会如何调节有组织的劳工实现其社会与经济目标的能力。
Abstract
Power is central to sociological accounts of economic inequality; however, buyer power-market conditions in which one or a few dominant employers can limit workers' outside options for employment-has received little attention relative to worker power. We study how the entry of Walmart Supercenters, the archetype of a high-buyer-power employer, affects the size and protective strength of union membership (a key dimension of worker power). We analyze (1) whether greater worker power dissuades Walmart Supercenters from entering a local labor market, (2) whether a successful Supercenter entry subsequently erodes local union membership, and (3) whether unions provide a protective effect against declining earnings after a successful Supercenter entry. We apply stacked difference-in-differences estimates based on county-year variation in Walmart Supercenter openings using restricted-access Panel Study of Income Dynamics data. We find that Walmart Supercenters are less likely to enter a local labor market that has high levels of union membership, even when conditioning on attempted Walmart entries. When Walmart Supercenter openings do occur, union membership declines by an average of 3.5 percentage points, and this is channeled through declining union membership in retail. Remaining union members are not protected against Walmart's downward pressure on earnings; in fact, annual earnings among workers who were unionized pre-treatment decline faster than for non-union members after a Walmart Supercenter opens. Worker power can be effective at preventing a rise in buyer power, but conditional on increases in buyer power, worker power tends to decline in terms of both size and protective strength. The sociological study of labor market power ought to consider how prevailing levels of buyer power can moderate the ability of organized labor to achieve its social and economic aims.