When wages rise, quality falls: Minimum wages and the hidden trade-off in competitive e-commerce markets
中文摘要
我们证明，在竞争极为激烈的数字市场中，产品与服务质量构成企业应对最低工资上调的一个隐性调整边际。利用2015年至2020年中国农村2628家天猫店铺的细粒度交易数据，并结合家户调查与企业层面数据，我们利用城市层面最低工资的交错上调，发现短期内企业既未减少就业，也未显著提价。相反，它们会系统性地降低质量——表现为产品评分下降、物流变慢与客户服务变差——该效应在两个季度内即开始显现，并随时间持续。中间投入的削减损害产品质量，而削减外包IT服务则通过弱化运营效率损害服务质量。至关重要的是，这一质量下降由高质量在位企业所驱动；低质量企业虽未显示变化，但在冲击之后更可能退出市场。这些结果揭示了劳动收入与消费者福利之间的权衡：这一成本在传统的劳动市场评估中不可见，却是完整福利评估的核心。
Abstract
We show that product and service quality serve as a hidden margin of adjustment to minimum wage hikes in hyper-competitive digital markets. Leveraging granular transaction data from 2628 Tmall stores in rural China from 2015 to 2020, combined with household surveys and firm-level data, we exploit staggered city-level minimum wage increases and find that in the short run, firms neither reduce employment nor significantly raise prices. Instead, they systematically degrade quality, as evidenced by worse product ratings, slower logistics, and poorer customer service, starting within two quarters and persisting over time. The reduction in intermediate inputs compromises product quality, while cuts to outsourced IT services undermine service quality by weakening operational efficiency. Crucially, this decline is driven by high-quality incumbents, whereas low-quality firms show no change but are more likely to exit the market following the shock. These results reveal a trade-off between labor income and consumer welfare, a cost that is invisible in traditional labor market evaluations but central to a complete welfare assessment.